Organotypic Slice Cultures for Studies of Postnatal Neurogenesis

Here we describe a technique for studying hippocampal postnatal neurogenesis in the rodent brain using the organotypic slice culture technique. This ...

National Yang-Ming University

Taipei City Hospital

Rats treated with low dose irradiation, to inhibit adult hippocampal neurogenesis, and control rats were administered a non-matching-to-sample (NMTS) task, which measured conditional rule learning and memory for specific events, and a test of fear conditioning in which a discrete CS was paired with an aversive US in a complex environment. Irradiated rats were impaired on the NMTS task when the intervals between sample and test trials were relatively long, and in associating the shock-induced fear with contextual cues in the fear conditioning task. Irradiated rats were not impaired in learning the basic NMTS rule or in performing that task when the intervals between the sample and test trials were short. Nor were there group differences in conditioning the fear response to the CS in the fear conditioning task. The results, which extend the range of hippocampus-dependent tasks that can be said to be vulnerable to the effects of neurogenesis suppression, support the hypothesis that new hippocampal cells generated in adulthood participate in a broad range of hippocampal functions.

Inhibition of neurogenesis interferes with hippocampus-dependent memory function.

AMPA &#x578B;&#x8C37;&#x6C28;&#x9178;&#x53D7;&#x4F53;&#x901A;&#x5E38;&#x662F;&#x7ECF;&#x9632;&#x6E17;&#x7531;&#x4E8E; GluR2 &#x53D7;&#x4F53;&#x4E9A;&#x5355;&#x4F4D;&#x7684;&#x8868;&#x8FBE;&#x3002;&#x901A;&#x8FC7;&#x4F7F;&#x7528; GluR2 &#x7A7A;&#x5C0F;&#x9F20;&#x6211;&#x4EEC;&#x80FD;&#x591F;&#x68C0;&#x6D4B;&#x5230;&#x4E86;&#x5FAE;&#x578B;&#x7A81;&#x89E6;&#x7ECF;&#x77AC;&#x53D8; (MSCTs) &#x4E0E; AMPA &#x578B;&#x53D7;&#x4F53;&#x4ECB;&#x5BFC;&#x7684;&#x5FAE;&#x578B;&#x7A81;&#x89E6;&#x7535;&#x6D41;&#x5728;&#x5355;&#x4E2A;&#x7A81;&#x89E6;&#x4E2D;&#x521D;&#x7EA7;&#x76AE;&#x5C42;&#x6587;&#x5316;&#x76F8;&#x5173;&#x8054;&#x3002;MSCTs &#x548C;&#x5173;&#x8054;&#x7684;&#x7ECF;&#x77AC;&#x53D8;&#x6761;&#x4EF6;&#x4E0B;&#x76D1;&#x6D4B;&#x9694;&#x79BB;&#x7684;&#x53CD;&#x5E94;&#x4ECB;&#x5BFC;&#x7684; AMPA &#x6216; N-&#x7532;&#x57FA;-D-&#x5929;&#x51AC;&#x6C28;&#x9178; (NMDA) &#x53D7;&#x4F53;&#x3002;&#x5982;&#x6240;&#x6599;&#xFF0C;&#x53E6;&#x5916; 6-cyano-7-nitroquinoxalene-2,3-dione &#x7684;&#x62EE;&#x6297;&#x5242; 3 microM CNQX&#xFF09; &#x963B;&#x6B62; AMPA &#x53D7;&#x4F53;&#x4ECB;&#x5BFC; MSCTs.&#x7535;&#x538B;&#x95E8;&#x63A7;&#x6027;&#x7684;&#x7ECF;&#x6E20;&#x9053;&#x4E0D;&#x4F1A;&#x52A9;&#x957F; AMPA MSCTs &#x56E0;&#x4E3A; CdCl(2) (0.1-0.2 m m&#xFF09; &#x5E76;&#x6CA1;&#x6709;&#x663E;&#x8457;&#x6539;&#x53D8;&#x9891;&#x7387;&#x6216; MSCTs &#x7684;&#x632F;&#x5E45;&#x3002;AMPA MSCTs &#x7684;&#x5E45;&#x5EA6;&#x4F3C;&#x4E4E;&#x53EF;&#x72EC;&#x7ACB;&#x8C03;&#x8282;&#x4ECE;&#x4E8B;&#x4EF6;&#x9891;&#x7387;&#x56E0;&#x4E3A;&#x8FD9;&#x4E24;&#x9879;&#x63AA;&#x65BD;&#x4E0D;&#x76F8;&#x5173; (R = 0.023&#xFF09;&#x3002;&#x7A81;&#x89E6;&#x7ED3;&#x6784;&#x786E;&#x5B9A;&#x4E86;&#xFF0C;&#x53EA;&#x8868;&#x793A; MSCTs &#x5F52;&#x56E0;&#x4E8E; NMDA &#x6216; AMPA &#x53D7;&#x4F53;&#x3002;&#x53EA;&#x6709; NMDA &#x53CD;&#x5E94;&#x4E0E;&#x795E;&#x7ECF;&#x7A81;&#x89E6;&#xFF0C;MSCT &#x632F;&#x5E45;&#x662F;&#x663E;&#x8457;&#x4E0B;&#x8DCC; (40%) &#x6BD4;&#x7A81;&#x89E6; NMDA &#x548C; AMPA &#x53CD;&#x5E94;&#x8868;&#x793A;&#x3002;&#x663E;&#x793A; MSCTs AMPA &#x548C; NMDA &#x53D7;&#x4F53;&#x4ECB;&#x5BFC;&#x7684;&#x7A81;&#x89E6;&#xFF0C;&#x5728;&#x77AC;&#x6001;&#x8FC7;&#x7A0B;&#x4E2D;&#x7684;&#x6BCF;&#x4E2A;&#x6761;&#x4EF6;&#x7684;&#x632F;&#x5E45;&#x5448;&#x663E;&#x8457;&#x6B63;&#x76F8;&#x5173; (R = 0.94)&#x3002;&#x6211;&#x4EEC;&#x7684;&#x7814;&#x7A76;&#x7ED3;&#x679C;&#x8868;&#x660E;&#x5F53; AMPA &#x548C; NMDA &#x53D7;&#x4F53;&#x5728;&#x7A81;&#x89E6;&#x591A;&#x53D1;&#x6027;&#x9AA8;&#x9AD3;&#x7624;&#xFF0C;&#x673A;&#x5236;&#x5B58;&#x5728;&#xFF0C;&#x786E;&#x4FDD;&#x6BCF;&#x4E2A;&#x4ECE;&#x7A81;&#x89E6;&#x524D;&#x56E0;&#x7D20;&#x63A7;&#x5236;&#x7684;&#x5FAE;&#x578B;&#x91CA;&#x653E;&#x9891;&#x7387;&#x4E0D;&#x540C;&#x7684;&#x53D7;&#x4F53;&#x7C7B;&#x578B;&#x7684;&#x6BD4;&#x4F8B;&#x7F29;&#x653E;&#x3002;

GluR2 AMPA &#x53D7;&#x4F53;&#x4ECB;&#x5BFC;&#x7684;&#x5FAE;&#x578B;&#x7A81;&#x89E6;&#x9499;&#x77AC;&#x53D8;&#x5C0F;&#x9F20;&#xFF0C;&#x5219;&#x4E3A; null&#x3002;

AMPA-type glutamate receptors are normally Ca(2+) impermeable due to the expression of the GluR2 receptor subunit. By using GluR2 null mice we were able to detect miniature synaptic Ca(2+) transients (MSCTs) associated with AMPA-type receptor-mediated miniature synaptic currents at single synapses in primary cortical cultures. MSCTs and associated Ca(2+) transients were monitored under conditions that isolated responses mediated by AMPA or N-methyl-D-aspartate (NMDA) receptors. As expected, addition of the antagonist 6-cyano-7-nitroquinoxalene-2,3-dione (CNQX, 3 microM) blocked the AMPA receptor-mediated MSCTs. Voltage-gated Ca(2+) channels did not contribute to AMPA MSCTs because CdCl(2) (0.1-0.2 mM) did not significantly alter the frequency or the amplitude of the MSCTs. The amplitude of AMPA MSCTs appeared to be regulated independently from event frequency since the two measures were not correlated (R = 0.023). Synapses were identified that only expressed MSCTs attributed to either NMDA or AMPA receptors. At synapses with only NMDA responses, MSCT amplitude was significantly lower (by 40%) than synapses expressing both NMDA and AMPA responses. At synapses that showed MSCTs mediated by both AMPA and NMDA receptors, the amplitude of the transients in each condition was positively correlated (R = 0.94). Our results suggest that when AMPA and NMDA receptors are co-expressed at synapses, mechanisms exist to ensure proportional scaling of each receptor type that are distinct from the presynaptic factors controlling the frequency of miniature release.

AMPA receptor-mediated miniature synaptic calcium transients in GluR2 null mice.

R&eacute;cepteurs de glutamate de type AMPA sont normalement Ca(2+) imperm&eacute;able en raison de l&#39;expression de la sous-unit&eacute; de r&eacute;cepteurs GluR2. En utilisant des souris null GluR2, que nous avons pu d&eacute;tecter transitoires de Ca(2+) synaptiques miniature (MSCTs) associ&eacute;es aux AMPA-type miniature m&eacute;di&eacute;e par les r&eacute;cepteurs courants synaptiques au niveau des synapses unique dans des cultures primaires corticales. MSCTs et associ&eacute;s Ca(2+) transitoires ont &eacute;t&eacute; suivies dans des conditions que les r&eacute;ponses isol&eacute;es m&eacute;di&eacute;e par AMPA ou N-m&eacute;thyl-D-aspartate (NMDA) r&eacute;cepteurs. Comme pr&eacute;vu, ajout de l&#39;antagoniste 6-cyano-7-nitroquinoxalene-2,3-dione (CNQX, microM 3) a bloqu&eacute; la Ca(2+) de MSCTs. Voltage-d&eacute;pendants de m&eacute;di&eacute;e par les r&eacute;cepteurs AMPA canaux ne contribue pas &agrave; la LPCA MSCTs parce que CdCl(2) (0,1 &agrave; 0,2 mM) n&#39;a pas significativement modifi&eacute; la fr&eacute;quence ou l&#39;amplitude de le MSCTs. L&#39;amplitude de l&#39;AMPA MSCTs semble &ecirc;tre r&eacute;gl&eacute;e ind&eacute;pendamment de la fr&eacute;quence d&#39;utilisation &eacute;tant donn&eacute; que les deux mesures n&#39;&eacute;taient pas corr&eacute;l&eacute;s (R = 0,023). Les synapses ont &eacute;t&eacute; identifi&eacute;s qui exprimait seulement MSCTs attribu&eacute;es aux r&eacute;cepteurs NMDA ou AMPA. Au niveau des synapses avec uniquement des r&eacute;ponses NMDA, amplitude de TDM a &eacute;t&eacute; significativement inf&eacute;rieur (40 %) que les synapses exprimant les r&eacute;ponses tant NMDA et AMPA. Au niveau des synapses qui a montr&eacute; MSCTs m&eacute;di&eacute;es par les r&eacute;cepteurs AMPA et NMDA fois, l&#39;amplitude des transitoires dans chaque condition &eacute;tait corr&eacute;l&eacute; (R = 0,94). Nos r&eacute;sultats sugg&egrave;rent que, lorsque les r&eacute;cepteurs AMPA et NMDA sont co-exprim&eacute;s aux synapses, des m&eacute;canismes existent pour assurer la mise &agrave; l&#39;&eacute;chelle proportionnelle de chaque type de r&eacute;cepteur qui se distinguent par pr&eacute;synaptiques facteurs contr&ocirc;lant la fr&eacute;quence de sortie de la miniature.

Transitoires de calcium synaptique miniature m&eacute;di&eacute;e par les r&eacute;cepteurs AMPA dans GluR2 null mice.

AMPA-Rezeptor-vermittelten Miniatur synaptischen Calcium-Transienten in M&#xE4;usen GluR2 null.

I recettori del glutammato di tipo AMPA sono normalmente Ca(2+) impermeabile a causa dell&#39;espressione della subunit&agrave; GluR2 del recettore. Utilizzando topi null GluR2, che siamo stati in grado di rilevare transitori di Ca(2+) sinaptiche in miniatura (MSCTs) associato all&#39;AMPA-tipo miniatura mediata dal recettore sinaptiche correnti a singole sinapsi in colture primarie corticali. MSCTs e associati Ca(2+) transitori sono stati monitorati in condizioni che risposte isolate mediata da AMPA o N-metil-D-aspartato (NMDA) recettori. Come previsto, aggiunta dell&#39;antagonista 6-cyano-7-nitroquinoxalene-2,3-dione (CNQX, 3 microM) bloccato l&#39;AMPA mediata dal recettore MSCTs. tensione-gated Ca(2+) canali non hanno contribuito a AMPA MSCTs perch&eacute; CdCl(2) (0.1-0.2 mM) non ha modificato significativamente la frequenza o l&#39;ampiezza dei MSCTs. L&#39;ampiezza dell&#39;AMPA MSCTs sembrava essere regolato indipendentemente dalla frequenza di eventi dal momento che le due misure non sono state correlate (R = 0,023). Sinapsi sono stati identificati solo espresso MSCTs attribuita ai recettori NMDA o AMPA. A sinapsi con solo risposte NMDA, ampiezza TCMS era significativamente inferiore (da 40%) di sinapsi esprimere risposte sia NMDA e AMPA. A sinapsi che ha mostrato MSCTs mediata dai recettori AMPA sia NMDA, l&#39;ampiezza dei transienti in ogni condizione &egrave; stata positivamente correlata (R = 0,94). I nostri risultati suggeriscono che quando i recettori AMPA e NMDA sono espressi in sinapsi, esistono meccanismi per assicurare il ridimensionamento proporzionale di ogni tipo di recettore che sono distinte dai presinaptico fattori che controllano la frequenza di rilascio in miniatura.

AMPA recettore-mediata in miniatura sinaptica calcio transitori nei topi null GluR2.

AMPA &#x578B;&#x30B0;&#x30EB;&#x30BF;&#x30DF;&#x30F3;&#x9178;&#x53D7;&#x5BB9;&#x4F53;&#x306F;&#x901A;&#x5E38;&#x30AB;&#x30EB;&#x30B7;&#x30A6;&#x30E0; glur2 &#x53D7;&#x5BB9;&#x4F53;&#x306E;&#x767A;&#x73FE;&#x306E;&#x305F;&#x3081;&#x306B;&#x4E0D;&#x6D78;&#x900F;&#x6027;&#x3067;&#x3059;&#x3002;&#x6211;&#x3005; &#x3092;&#x691C;&#x51FA;&#x3059;&#x308B;&#x3053;&#x3068;&#x304C;&#x3067;&#x304D;&#x305F; GluR2 null &#x30DE;&#x30A6;&#x30B9;&#x3092;&#x7528;&#x3044;&#x3066;&#x30DF;&#x30CB;&#x30C1;&#x30E5;&#x30A2; &#x30B7;&#x30CA;&#x30D7;&#x30B9; &#x30AB;&#x30EB;&#x30B7;&#x30A6;&#x30E0; &#x30C8;&#x30E9;&#x30F3;&#x30B8;&#x30A7;&#x30F3;&#x30C8; &#xFF08;MSCTs&#xFF09; &#x5358;&#x4E00;&#x30B7;&#x30CA;&#x30D7;&#x30B9; &#x30D7;&#x30E9;&#x30A4;&#x30DE;&#x30EA;&#x76AE;&#x8CEA;&#x57F9;&#x990A;&#x3067; AMPA &#x578B;&#x53D7;&#x5BB9;&#x4F53;&#x3092;&#x4ECB;&#x3057;&#x305F;&#x30DF;&#x30CB;&#x30C1;&#x30E5;&#x30A2;&#x6027;&#x30B7;&#x30CA;&#x30D7;&#x30B9;&#x96FB;&#x6D41;&#x95A2;&#x9023;&#x4ED8;&#x3051;&#x3089;&#x308C;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;MSCTs &#x304A;&#x3088;&#x3073;&#x95A2;&#x9023;&#x4ED8;&#x3051;&#x3089;&#x308C;&#x3066;&#x3044;&#x308B;&#x30AB;&#x30EB;&#x30B7;&#x30A6;&#x30E0; &#x30C8;&#x30E9;&#x30F3;&#x30B8;&#x30A7;&#x30F3;&#x30C8;&#x6761;&#x4EF6;&#x4E0B;&#x3067;&#x5206;&#x96E2;&#x5FDC;&#x7B54; AMPA &#x307E;&#x305F;&#x306F; N-&#x30E1;&#x30C1;&#x30EB;-D-&#x30A2;&#x30B9;&#x30D1;&#x30E9;&#x30AE;&#x30F3;&#x9178; (NMDA) &#x53D7;&#x5BB9;&#x4F53;&#x5A92;&#x4ECB;&#x76E3;&#x8996;&#x3055;&#x308C;&#x307E;&#x3057;&#x305F;&#x3002;&#x4E88;&#x60F3;&#x901A;&#x308A;&#x3001;&#x6DFB;&#x52A0; 6-cyano-7-nitroquinoxalene-2,3-dione &#x306E;&#x62EE;&#x6297;&#x85AC; (CNQX, 3 microM) &#x30C1;&#x30E3;&#x30F3;&#x30CD;&#x30EB;&#x5BC4;&#x4E0E;&#x3057;&#x306A;&#x304B;&#x3063;&#x305F; AMPA MSCTs &#x3059;&#x308B;&#x306E;&#x3067;&#x3001;AMPA &#x53D7;&#x5BB9;&#x4F53;&#x3092;&#x4ECB;&#x3057;&#x305F; MSCTs &#x96FB;&#x5727;&#x30B2;&#x30FC;&#x30C8; &#x30AB;&#x30EB;&#x30B7;&#x30A6;&#x30E0; &#x30D6;&#x30ED;&#x30C3;&#x30AF; CdCl(2) &#xFF08;0.1 &#xFF5E; 0.2 mM&#xFF09; &#x5927;&#x5E45;&#x306B;&#x5468;&#x6CE2;&#x6570;&#x307E;&#x305F;&#x306F;&#x3001;MSCTs &#x306E;&#x632F;&#x5E45;&#x306F;&#x5909;&#x308F;&#x308A;&#x307E;&#x305B;&#x3093;&#x3067;&#x3057;&#x305F;&#x3002;2 &#x3064;&#x306E;&#x5BFE;&#x7B56;&#x306E;&#x76F8;&#x95A2;&#x304C;&#x8A8D;&#x3081;&#x3089;&#x308C;&#x305F;&#x3044;&#x306A;&#x3044;&#x306E;&#x3067;&#x72EC;&#x7ACB;&#x3057;&#x3066;&#x30A4;&#x30D9;&#x30F3;&#x30C8;&#x306E;&#x983B;&#x5EA6;&#x304B;&#x3089;&#x898F;&#x5236;&#x3057;&#x306A;&#x3044;&#x3059;&#x308B; AMPA MSCTs &#x306E;&#x632F;&#x5E45;&#x304C;&#x767B;&#x5834; (R = 0.023)&#x3002;&#x30B7;&#x30CA;&#x30D7;&#x30B9;&#x3060;&#x3051;&#x8868;&#x73FE;&#x8D77;&#x56E0;&#x3059;&#x308B; NMDA &#x307E;&#x305F;&#x306F; AMPA &#x53D7;&#x5BB9;&#x4F53; MSCTs &#x3092;&#x540C;&#x5B9A;&#x3057;&#x307E;&#x3057;&#x305F;&#x3002;NMDA &#x5FDC;&#x7B54;&#x306E;&#x307F;&#x3067;&#x306E;&#x30B7;&#x30CA;&#x30D7;&#x30B9;&#x3067;&#x306B;&#x3088;&#x308B;&#x632F;&#x5E45;&#x30B7;&#x30CA;&#x30D7;&#x30B9;&#x306E; NMDA &#x53CA;&#x3073; AMPA &#x306E;&#x30EC;&#x30B9;&#x30DD;&#x30F3;&#x30B9;&#x3092;&#x8868;&#x73FE;&#x3059;&#x308B;&#x3088;&#x308A;&#x3082; &#xFF08;40 &#xFF05;&#xFF09; &#x4F4E;&#x304B;&#x3063;&#x305F;&#x3002;AMPA &#x3068; NMDA &#x53D7;&#x5BB9;&#x4F53;&#x3092;&#x4ECB;&#x3059;&#x308B; MSCTs &#x3092;&#x793A;&#x3057;&#x305F;&#x30B7;&#x30CA;&#x30D7;&#x30B9;&#x3067;&#x306F;&#x3001;&#x5404;&#x6761;&#x4EF6;&#x306B;&#x304A;&#x3051;&#x308B;&#x904E;&#x6E21;&#x73FE;&#x8C61;&#x306E;&#x632F;&#x5E45;&#x76F8;&#x95A2;&#x3060;&#x3063;&#x305F; (R = 0.94)&#x3002;AMPA &#x3068; NMDA &#x53D7;&#x5BB9;&#x4F53;&#x30B7;&#x30CA;&#x30D7;&#x30B9;&#x3067;&#x30B7;&#x30E7;&#x30A6;&#x30B8;&#x30E7;&#x30A6;&#x30D0;&#x30A8;&#x30B2;&#x30CE;&#x30E0;&#x3068;&#x304D;&#x3001;&#x30E1;&#x30AB;&#x30CB;&#x30BA;&#x30E0;&#x306B;&#x6BD4;&#x4F8B;&#x30B9;&#x30B1;&#x30FC;&#x30EA;&#x30F3;&#x30B0;&#x3092;&#x30DF;&#x30CB;&#x30C1;&#x30E5;&#x30A2; &#x30EA;&#x30EA;&#x30FC;&#x30B9;&#x306E;&#x983B;&#x5EA6;&#x3092;&#x5236;&#x5FA1;&#x3059;&#x308B;&#x30B7;&#x30CA;&#x30D7;&#x30B9;&#x524D;&#x306E;&#x8981;&#x56E0;&#x304B;&#x3089;&#x533A;&#x5225;&#x3055;&#x308C;&#x308B;&#x5404;&#x53D7;&#x5BB9;&#x4F53;&#x30BF;&#x30A4;&#x30D7;&#x306E;&#x5B58;&#x5728;&#x304C;&#x793A;&#x5506;&#x3055;&#x308C;&#x307E;&#x3057;&#x305F;&#x3002;

AMPA &#x53D7;&#x5BB9;&#x4F53;&#x3092;&#x4ECB;&#x3057;&#x305F;&#x30DF;&#x30CB;&#x30C1;&#x30E5;&#x30A2; &#x30B7;&#x30CA;&#x30D7;&#x30B9; &#x30AB;&#x30EB;&#x30B7;&#x30A6;&#x30E0; &#x30C8;&#x30E9;&#x30F3;&#x30B8;&#x30A7;&#x30F3;&#x30C8; GluR2 &#x6B20;&#x640D;&#x30DE;&#x30A6;&#x30B9;&#x3067;&#x306F;&#x3002;

AMPA &#xD615; glutamate &#xC218;&#xC6A9; &#xCCB4;&#xB294; &#xC77C;&#xBC18;&#xC801;&#xC73C;&#xB85C; Ca(2+) GluR2 &#xC218;&#xC6A9; &#xCCB4; &#xC18C; &#xB2E8;&#xC704; &#xC2DD;&#xC73C;&#xB85C; &#xC2A4;&#xBA70;&#xB4E4; &#xC9C0; &#xC54A;&#xB294;. GluR2 null &#xB9C8;&#xC6B0;&#xC2A4; &#xAC10;&#xC9C0; &#xC218;&#xB97C; &#xC0AC;&#xC6A9; &#xD558; &#xC5EC; &#xBBF8;&#xB2C8;&#xC5B4;&#xCC98; &#xC2DC; &#xB0C5; &#xC2A4; Ca(2+) &#xACFC;&#xB3C4; (MSCTs) &#xAE30;&#xBCF8; &#xB300;&#xB1CC; &#xD53C; &#xC9C8;&#xC758; &#xBB38;&#xD654;&#xC5D0;&#xC11C; &#xB2E8;&#xC77C; &#xC2DC; &#xB0C5; &#xC2A4;&#xC5D0;&#xC11C; AMPA &#xD615; &#xC218;&#xC6A9; &#xCCB4;-&#xC911;&#xC7AC; &#xBBF8;&#xB2C8;&#xC5B4;&#xCC98; &#xC2DC; &#xB0C5; &#xC2A4; &#xC804;&#xB958;&#xC640; &#xAD00;&#xB828; &#xB41C;. MSCTs &#xBC0F; &#xAD00;&#xB828;&#xB41C; Ca(2+) &#xACFC;&#xB3C4; &#xACA9;&#xB9AC; &#xB41C; &#xC751;&#xB2F5; AMPA &#xB610;&#xB294; N-&#xBA54; &#xD2F8;-D-aspartate (NMDA)&#xC5D0; &#xC758;&#xD574; &#xC218;&#xC6A9; &#xCCB4; &#xC911;&#xC7AC;&#xB294; &#xC870;&#xAC74; &#xD558;&#xC5D0;&#xC11C; &#xAC10;&#xC2DC; &#xB418;&#xC5C8;&#xB2E4;. 6-Cyano-7-nitroquinoxalene-2,3-dione &#xAE38; &#xD56D; &#xC81C; (CNQX, 3 microM) &#xCD94;&#xAC00; &#xCC28;&#xB2E8; &#xB41C; AMPA &#xC218;&#xC6A9; &#xCCB4;-&#xC911;&#xC7AC; MSCTs. &#xC804;&#xC555; &#xAC1C;&#xD3D0; Ca(2+) &#xB54C;&#xBB38;&#xC5D0; &#xCC44;&#xB110; AMPA Mscts&#xC5D0; &#xAE30;&#xC5EC; &#xD558;&#xC9C0; &#xC54A;&#xC558;&#xB2E4; &#xC608;&#xC0C1; &#xD588;&#xB358; &#xB300;&#xB85C;, CdCl(2) (0.1-0.2 m m)&#xB294; Mscts&#xC758; &#xC9C4;&#xD3ED; &#xB610;&#xB294; &#xC8FC;&#xD30C;&#xC218; &#xB300;&#xD3ED; &#xBCC0;&#xACBD; &#xD558;&#xC9C0; &#xC54A;&#xC558;&#xB2E4;. AMPA MSCTs &#xC9C4;&#xD3ED; &#xADDC;&#xC81C; &#xB418;&#xC5B4;&#xC57C; &#xD558;&#xC9C0; &#xB3C5;&#xB9BD;&#xC801;&#xC73C;&#xB85C; &#xC774;&#xBCA4;&#xD2B8; &#xC8FC;&#xD30C;&#xC218;&#xC5D0;&#xC11C; &#xB450; &#xAC00;&#xC9C0; &#xC870;&#xCE58;&#xB97C; &#xC0C1;&#xAD00; &#xD558;&#xC9C0; &#xD588;&#xB2E4; &#xC774;&#xD6C4; &#xB098;&#xD0C0;&#xB0AC;&#xB2E4; (R = 0.023). &#xB0C5; MSCTs NMDA &#xB610;&#xB294; AMPA &#xC218;&#xC6A9; &#xCCB4;&#xC5D0;&#xB9CC; &#xD45C;&#xD604; &#xB418;&#xB294; &#xAC83;&#xC744; &#xBC1C;&#xACAC; &#xD588;&#xB2E4;. AMPA &#xBC0F; NMDA &#xC751;&#xB2F5; &#xD45C;&#xD604; synapses &#xBCF4;&#xB2E4; NMDA &#xBC18;&#xC751;&#xB9CC; &#xB0C5; MSCT &#xC9C4;&#xD3ED; (40%)&#xB85C; &#xC0C1;&#xB2F9;&#xD788; &#xB0AE;&#xC740; &#xD588;&#xB2E4;. MSCTs &#xC911;&#xC7AC; AMPA &#xBC0F; NMDA &#xC218;&#xC6A9; &#xCCB4;&#xB294; &#xC2DC; &#xB0C5; &#xC2A4;&#xC5D0;&#xC11C; &#xAC01; &#xC870;&#xAC74;&#xC5D0; &#xACFC;&#xB3C4;&#xC758; &#xC9C4;&#xD3ED;&#xC740; &#xAE0D;&#xC815;&#xC801;&#xC73C;&#xB85C; &#xC0C1;&#xAD00; &#xAD00;&#xACC4; (R = 0.94). &#xC6B0;&#xB9AC;&#xC758; &#xACB0;&#xACFC; &#xAC74;&#xC758; AMPA &#xBC0F; NMDA &#xC218;&#xC6A9; &#xCCB4;&#xB294; &#xC2DC; &#xB0C5; &#xC2A4;&#xC5D0;&#xC11C; co-expressed, &#xBA54;&#xCEE4;&#xB2C8;&#xC998; &#xBBF8;&#xB2C8;&#xC5B4;&#xCC98; &#xCD9C;&#xC2DC;&#xC758; &#xC8FC;&#xD30C;&#xC218; &#xC81C;&#xC5B4; presynaptic &#xC694;&#xC778; &#xC73C;&#xB85C;&#xBD80;&#xD130; &#xACE0;&#xC720; &#xC218;&#xC6A9; &#xCCB4; &#xC885;&#xB958;&#xBCC4;&#xB85C; &#xBE44;&#xB840; &#xBC30;&#xC728; &#xC870;&#xC815; &#xBCF4;&#xC7A5; &#xD558;&#xAE30; &#xC704;&#xD574; &#xC874;&#xC7AC; &#xD55C;&#xB2E4;.

Glur2&#xC5D0;&#xC11C; AMPA &#xC218;&#xC6A9; &#xCCB4;-&#xC911;&#xC7AC; &#xBBF8;&#xB2C8;&#xC5B4;&#xCC98; &#xC2DC; &#xB0C5; &#xC2A4; &#xCE7C;&#xC298; &#xACFC;&#xB3C4; &#xC950; null&#xC785;&#xB2C8;&#xB2E4;.

Receptores de glutamato tipo AMPA suelen CA impermeable debido a la expresi&oacute;n de la subunidad del receptor de GluR2. Utilizando ratones nulos GluR2, que hemos sido capaces de detectar transitorios de CA sin&aacute;pticas de miniatura (MSCTs) asociados con corrientes sin&aacute;pticas mediada por receptor miniatura de tipo AMPA en las sinapsis solas en cultivos primarios de corticales. MSCTs y asociados CA transitorios fueron supervisados bajo condiciones que aislados de las respuestas mediaron por AMPA o N-metil-D-aspartato (NMDA) receptores. Como era de esperar, adem&aacute;s del antagonista 6-cyano-7-nitroquinoxalene-2,3-dione (CNQX, 3 microM) bloquearon el AMPA mediada por receptor MSCTs. voltaje CA canales no contribuy&oacute; al AMPA MSCTs porque CdCl(2) (0.1-0.2 mM) no alter&oacute; significativamente la frecuencia o la amplitud de las MSCTs. La amplitud del AMPA MSCTs parece regular independientemente de la frecuencia del evento ya que las dos medidas no se correlacionaron (R = 0.023). Las sinapsis se identificaron que s&oacute;lo expres&oacute; MSCTs atribuidos a los receptores de NMDA o AMPA. En las sinapsis con s&oacute;lo las respuestas NMDA, amplitud MSCT fue significativamente menor (en un 40%) de sinapsis expresando respuestas tanto NMDA y AMPA. En las sinapsis que demostraron MSCTs mediadas por receptores NMDA tanto AMPA, la amplitud de los transitorios en cada Estado se correlacion&oacute; positivamente (R = 0.94). Nuestros resultados sugieren que cuando los receptores AMPA y NMDA son co-expressed en las sinapsis, existen mecanismos para asegurar la escala proporcional de cada tipo de receptor que se distinguen de los factores presin&aacute;pticos controla la frecuencia de lanzamiento de miniatura.

Transitorios en ratones nulos GluR2 en AMPA miniatura mediada por receptor calcio sin&aacute;ptica.

Injury to the brain often results in loss of synapses or cell death in the damaged area. Subsequent to the injury, the areas that are not directly affected often exhibit enhanced neuronal plasticity. Although there are many reports of morphological changes resulting from such plasticity, their functional consequences are poorly understood. In this study we examined electrophysiological changes associated with ischemia-induced neurogenesis in the hippocampus, a brain region that is particularly vulnerable but also exceptionally plastic. Transient global ischemia was induced in Sprague-Dawley rats by occlusion of both carotid arteries and a reduction in blood pressure for 12 min. The procedure resulted in delayed cell death in the CA1 field of the hippocampus while the dentate gyrus (DG) was spared. To assess neurogenesis and synaptic changes in parallel we used both hemispheres from each animal. One side was used for immunohistochemistry and the other for in vitro electrophysiological experiments in brain slices. Synaptic field responses and synaptic plasticity (LTP) in perforant path within the DG were reduced by 50% at 10 days after the ischemic injury but recovered at 35 days. Synaptic responses in non-neurogenic CA1 were abolished in parallel with cell death and did not recover. Gamma irradiation applied focally to the head selectively prevented neurogenesis and the synaptic recovery in the DG. These experiments reveal electrophysiological changes associated with reactive neural plasticity in the hippocampus.

Electrophysiological correlates of neural plasticity compensating for ischemia-induced damage in the hippocampus.

We have reported previously that prenatal bacterial lipopolysaccharide (LPS) exposure at the gestation window of vulnerability could consistently lead to dopamine (DA) neuron loss in the substantia nigra (SN). Thus, we suggested that prenatal LPS exposure might represent as a risk factor for the development of Parkinson's disease (PD). Here, we report that the same exposure could lead to tryptophan hydroxylase (TPH, a serotonin neuron marker) immunoreactive cell loss in the dorsal raphe nucleus (DRN). Twenty two pups born to saline or LPS-injected gravid female rats at E10.5 were used in the current study. Twelve male pups at age of 4 months (6 from each of two prenatal groups) were used for the tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH) immunochemistry studies. The other 10 (5 from each of two prenatal groups) males were used in the biochemistry studies. A 29% THir neuron loss in the substantia nigra (F(1,11)=17.573, P=0.002) and a 31% TPHir neuron loss (F(1,11)=44.005, P<0.001) in the DRN were seen. Significant DA and 5-hydroxytryptamine (5-HT) reductions (P<0.05) were found in the frontal cortex, nucleus accumbens, striatum, amygdala, hippocampus, and hypothalamus. The losses of DA and 5-HT were accompanied by the significant increases in homovanillic acid over DA and 5-hydroxyindoleacetic acid over 5-HT ratios in the most areas tested. These data further validate prenatal LPS exposure as a model of PD since DA and 5-HT changes similar to those seen in PD patients. They also suggest that prenatal LPS might be a risk factor for other diseases including mood disorders.

Dopaminergic and serotoninergic deficiencies in young adult rats prenatally exposed to the bacterial lipopolysaccharide.

Hypothalamic-pituitary-adrenal (HPA) axis dysfunction has been implicated in depression pathology. In the present study, we used a chronic mild stress (CMS) animal model of depression to examine the responses of three strains of rats that have different HPA axis responsiveness; and whether the behavioral changes observed are correlated with changes in hippocampal cell proliferation and survival. In addition, in most of the CMS experiments the rats are kept in singly housed condition. Since rats are social animals we also examined whether prolonged single housing condition affects the behavior of the rats. The results showed that rats with a hyperactive HPA axis, the inbred Fischer (F344) rat, were the most responsive to CMS. The inbred Lewis (LEW) rat, which has a hypoactive HPA axis, did not show anhedonia after CMS treatment but showed other signs of distress. The responses of the outbred Sprague-Dawley (SD) rats were variable; this strain was very sensitive to the single housing condition. Prolonged single housing condition itself could induce helplessness behavior in the rats. The results from hippocampal cell proliferation of the three strains indicated that cell proliferation was not related to anhedonia induced by CMS. We conclude that F344 rat is the strain most sensitive to CMS treatment and is probably the stain of choice for CMS experiments.

Strain differences in the chronic mild stress animal model of depression.

Maternal infection during pregnancy may affect fetal brain development and lead to neurological and mental disorders. Previously, we used lipopolysaccharide [LPS, 33 μg/kg, intraperitoneal injection] exposure on gestation day 10.5 to mimic maternal bacterial infection in rats and found reduced dopaminergic and serotoninergic neurons in the offspring. In the present study, we examined the anxiety and stress responses of the affected offspring and the neurophysiological changes in their brains. Our results show that LPS rats displayed more anxiety-like behaviors and heightened stress responses. Dopamine (DA) in the nucleus accumbens and serotonin (5-HT) in the medial prefrontal cortex and the hippocampus were significantly reduced in LPS rats. Their glucocorticoid receptors in the dorsal hippocampus and the 5-HT(1A) receptors in the dorsal and ventral hippocampus were also reduced. In addition, chronic but not acute fluoxetine treatment reversed the behavioral changes and increased hippocampal 5-HT(1A) receptor expression. This study demonstrates that LPS exposure during a critical time of embryonic development could produce long-term reduction of DA and 5-HT and other neurophysiological changes; such alterations may be associated with the increases in stress response and anxiety-like behaviors in the offspring.

Prenatal lipopolysaccharide exposure increases anxiety-like behaviors and enhances stress-induced corticosterone responses in adult rats.

Major depression is one of the most prevalent mental disorders in the population. In addition to genetic influences, disturbances in fetal nervous system development might be a contributing factor. Maternal infection during pregnancy may affect fetal brain development and consequently lead to neurological and mental disorders. Previously, we used low-dose lipopolysaccharide (LPS) exposure on embryonic day 10.5 to mimic mild maternal infection in rats and found that dopaminergic and serotonergic neurons were reduced in the offspring. The offspring also showed more anxiety-like behavior and an enhanced stress response. In the present study we used forced swim test and chronic mild stress challenge to assess depression-like behaviors in the affected offspring and examined their adult hippocampal neurogenesis and brain-derived neurotrophic factor (BDNF) concentration. Our results showed that prenatally LPS-exposed rats (LPS rats) displayed more depression-like behaviors and had reduced adult neurogenesis and BDNF. The behavioral abnormalities and reduction in adult neurogenesis could be reversed by chronic fluoxetine (FLX) treatment. This study demonstrates that during the critical time of embryonic development LPS exposure can produce long-term behavioral changes and reduction in adult neurogenesis. The findings of enhanced depression-like behaviors, reduced adult neurogenesis, and their responsiveness to chronic antidepressant treatment suggest that prenatal LPS exposure could serve as an animal model of depression.

Sabrina Wang

Institute of Anatomy and Cell Biology,
School of Medicine,
Institute of Anatomy and Cell Biology, School of Medicine

National Yang-Ming University

Organotypic Slice Cultures for Studies of Postnatal Neurogenesis

Sabrina Wang

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Institute of Anatomy and Cell Biology,School of Medicine,Institute of Anatomy and Cell Biology, School of Medicine

National Yang-Ming University

Organotypic Slice Cultures for Studies of Postnatal Neurogenesis

Institute of Anatomy and Cell Biology,
School of Medicine,
Institute of Anatomy and Cell Biology, School of Medicine