Lateral septum adenosine A2A receptors control stress-induced depressive-like behaviors via signal-ing to hypothalamus and habenula / 中国药理学与毒理学杂志

Depressive disorder ranks as a major bur-den of disease worldwide,yet the current antidepressant medications are limited by frequent non-responsiveness and significant side effects.The lateral septum(LS)is thought to control of depression,however,the cellular and circuit substrates are largely unknown.Here,we identified a subpopulation of LS GABAergic adenosine A2A receptors(A2AR)-positive neurons mediating depres-sive symptoms via direct projects to the lateral habenula(LHb)and the dorsomedial hypothalamus(DMH).Activa-tion of A2AR in the LS augmented the spiking frequency of A2AR-positive neurons leading to a decreased activation of surrounding neurons and the bi-directional manipula-tion of LS-A2AR activity demonstrated that LS-A2ARs are necessary and sufficient to trigger depressive pheno-types.Thus,the optogenetic modulation(stimulation or inhibition)of LS-A2AR-positive neuronal activity or LS-A2AR-positive neurons projection terminals to the LHb or DMH,phenocopied depressive behaviors.Moreover,A2AR are upregulated in the LS in two male mouse mod-els of repeated stress-induced depression.This identifica-tion that aberrantly increased A2AR signaling in the LS is a critical upstream regulator of repeated stress-induced depressive-like behaviors provides a neurophysiological and circuit-based justification of the antidepressant poten-tial of A2AR antagonists,prompting their clinical transla-tion.

A circuit from dorsal hippocampal CA3 to parvafox nucleus mediates social novelty preference deficits induced by chronic social defeat stress / 中国药理学与毒理学杂志

OBJECTIVE The preference for social novelty is crucial to the social life of humans and rodents.However,the neural mechanisms underlying social novelty preference are poorly understood.Dorsal hippocampal CA3(dCA3)is an important brain area that responds to social defeat stress,and the neural circuitry of dCA3→lat-eral septum(LS)participates in the context-associated memory.Meanwhile,the parvafox nucleus(PFN)Foxb1+ neurons regulate the defensive reaction to life-threaten-ing situations.Therefore,we investigate a cell-specific cir-cuit of dCA3CaMKⅡα+→dorsal LSGABA+→PFNFoxb1+ in social novelty preference.METHODS Chronic social defeat stress(CSDS)and three-chamber social interaction test were performed in adult male C57BL/6J mice to detect social behaviors.Optogenetic and chemical-genetic experiments were conducted to regulate the circuit.RESULTS CSDS reduced the preference for social nov-elty in mice and the response of dCA3CaMKⅡα+ neurons dur-ing approach to an unfamiliar mouse was impaired by CSDS.Optogenetic inhibition of dCA3CaMKⅡα+→dLS pro-jection reduced the preference for the unfamiliar mouse versus a familiar mouse.Meanwhile,optogenetic activa-tion of dCA3CaMKⅡα+→dLS projection rescued the prefer-ence for social novelty of CSDS-treated mice.Manipula-tions dLSGABA+→PFN projection activation regulated the preference for social novelty in mice.Optogenetic activa-tion of PFNFoxb1+→lPAG projection reduced the prefer-ence for a familiar C57BL/6J mouse versus a novel object in control mice.CSDS decreased the excitability of dCA3CaMKⅡα+ neurons by up-regulation of Kir2.4(Kcnj14)expression.CONCLUSION Our present study suggest-ed that activation of a cell-specific circuit of dCA3CaMKⅡα+→dLSGABA+→PFNFoxb1+→lPAG reverses the deficits of social novelty preference in defeated mice,and inhibition of this circuit reduces the preference for social novelty.The cir-cuit that regulates the preference for social novelty deficits may provide a new information for the potential therapeu-tic targets for neuropsychiatric diseases.

Changes in c-Fos Expression in the Forced Swimming Test: Common and Distinct Modulation in Rat Brain by Desipramine and Citalopram

Rodents exposed to a 15-min pretest swim in the forced swimming test (FST) exhibit prolonged immobility in a subsequent 5-min test swim, and antidepressant treatment before the test swim reduces immobility. At present, neuronal circuits recruited by antidepressant before the test swim remain unclear, and also less is known about whether antidepressants with different mechanisms of action could influence neural circuits differentially. To reveal the neural circuits associated with antidepressant effect in the FST, we injected desipramine or citalopram 0.5 h, 19 h, and 23 h after the pretest swim and observed changes in c-Fos expression in rats before the test swim, namely 24 h after the pretest swim. Desipramine treatment alone in the absence of pretest swim was without effect, whereas citalopram treatment alone significantly increased the number of c-Fos-like immunoreactive cells in the central nucleus of the amygdala and bed nucleus of the stria terminalis, where this pattern of increase appears to be maintained after the pretest swim. Both desipramine and citalopram treatment after the pretest swim significantly increased the number of c-Fos-like immunoreactive cells in the ventral lateral septum and ventrolateral periaqueductal gray before the test swim. These results suggest that citalopram may affect c-Fos expression in the central nucleus of the amygdala and bed nucleus of the stria terminalis distinctively and raise the possibility that upregulation of c-Fos in the ventral lateral septum and ventrolateral periaqueductal gray before the test swim may be one of the probable common mechanisms underlying antidepressant effect in the FST.

Role of Lateral Septum-ACh Pressor System in Central Amygdaloid Nucleus-emotional Pressor System / 医学研究杂志

Objective The present study was to analyze the role of ACh-lateral septum(SL)pressor system in the Central amygdaloid nucleus(AC)-emotional pressor circuit.Method Interurban microinjection of different drugs,then blood pressure and heart vate were vecorded.Results(1)CRF(corticotropin releasing factor)or SP(substance P)microinjection into the SL can induced pressor responses.The AC pressor responses to glutamate(Glu)could be attenuated by preinjection of CRF antagonist or SP antagonist into bilateral SL.(2)the AC pressor responses to Glu were also reduced by preinjection of atropine into either bilateral HBL,LC or RVL respectively,(3)Since lateral HB(HBL)projects to the posterior hypothalamus(HP)containing ACh-ergic neurons,and excitation of the latter produces pressor response via the RVL and LC-RVL;atropine preinjection into the HP could also decrease the HBL-and AC-pressor response.Conclusion The present results indicate that the AC produce pressor responses involved with the SL via their CRF and SP,mechanism underlying pressor response of SL is involved in pressor response of AC.

Effects of Repeated Stress on Expression of Corticotropin Releasing Factor Type I and II Receptors / 신경정신의학

OBJECTIVES: Corticotropin releasing factor (CRF) plays a primary role in coordinating the neuroendocrine, autonomic, immune and behavioral responses to stress. CRF exerts its action through two major receptors, corticotropin-releasing factor 1 Receptor (CRF-R1) and corticotropin-releasing factor 2 receptor (CRF-R2). Using two types of chronic stress models, we investigated the changes of CRF-R1 mRNA and CRF-R2A mRNA expressions and CRF mRNA in the stress related brain circuit areas. METHODS: Male Sprague-Dawley rats were exposed to either immobilization stress or variable intermittent unpredictable stress for 10 days and then in situ hybridization histochemistry was used to quantify CRF expression in the brain. RESULTS: 1) CRF1 receptor mRNA expressions were decreased in bed nucleus stria terminalis (BNST) following stressors. 2) CRF2A receptor mRNA expressions were increased in lateral septum following stressors. 3) CRF mRNA expressions were increased in central nucleus of amygdala (CeA) and BNST. CONCLUSION: The increased CRF mRNA of CeA and BNST may be related with anxiety response in the repeated stress. Down-regulation of CRF-R1 mRNA expression in BNST may represent a compensatory adaptation to chronic stress and may be involved in the anxiety response, whereas up-regulation of CRF-R2A mRNA expression in lateral septum may represent an anxiety response or impaired learning but the functional meaning is uncertain.