NMDA and group I metabotropic glutamate receptors activation modulates substance P release from the arcuate nucleus and median eminence.

C. CARUSO; D. DURAND; H. WATANOBE; M. LASAGA

San Diego

Congreso; The Endocrine Society´s 87th annual meeting; 2005

The Endocrine Society

Glutamate participates in the regulation of secretion of several neuropeptides, including substance P (SP). Glutamate acts through ionotropic (iGluRS) and metabotropic (mGluRS) receptors. The iGluRS are subdivided in NMDA, kainate and AMPA receptors while mGluRs are classified into three groups. NMDA receptors have been proved to increase SP release from striatal neurons and from rat spinal cord. In order to determine if iGluRs and mGluRs receptor activation plays a role in the modulation of hypothalamic SP release in male rats, we investigated whether glutamate receptors agonists and antagonists could affect SP release from hypothalamic fragments containing the arcuate nucleus and the median eminence (ARC/ME). SP-like immunoreactivity (SP-LI) was determined by RIA.An increase in SP-LI release from ARC/ME was induced by glutamate (Control: 5.61 ±0.43 ng/mg protein; Glu 0.1 mM: 9.22 ±0.33, p