Effects of AP-V and bicuculline on somatostatin-positive neurons in hypothalamus of rats subjected to acute hypobaric hypoxia

AIM: To investigate the effects of 2-amino-5-phosphonovalerate-pharmacology (AP-V) and bicuculline on somatostatin (SST)-positive neurons in hypothala mus of rats subjected to acute hypobaric hypoxia. METHODS: SST-immunoreacti vity (IR) and somatostatin mRNA (SS mRNA)-positive neurons were measured by immunohistochemistry and in situ hybridization methods. RESULTS: Compared with control rats, SST-IR and SS mRNA-positive neurons in hypothalamic peri ventricular nucleus (PeV), paraventricular nucleus (PVN), and arcuate nucle us (ARC) increased after acute hypobaric hypoxia for 6 h (P < 0.101), and t hese effects were markedly inhibited by AP-V (10 <mu>g, icv), a highly sele ctive N-methyl-D-aspartate (MMDA) receptor antagonist, whereas were strongl y enhanced by bicuculline (1.5 mg.kg(-1), ip), a gamma-aminobutyric acid (G ABA(A)) receptor antagonist. CONCLUSION: SST possibly participates in acute hypoxic reaction in hypothalamus, furthermore, glutamate and GABA can affe ct somatostatin release and synthesis in hypothalamus through NMDA and GABA (A) receptors respectively.