Studies on the origin and release of somatostatin-immunoreactivity in the nucleus of the solitary tract.
The somatostatin content of the nucleus of the solitary tract (NTS) was regionally distributed within the nucleus and a calcium-dependent release of the neuropeptide was evoked by potassium-induced depolarization in vitro. The origin of the somatostatin in the NTS was studied with various denervation procedures. Unilateral NTS deafferentation decreased the concentration of somatostatin in the NTS. However, neither midbrain hemisection nor nodose ganglionectomy reduced the somatostatin content of the NTS. In addition, the nodose ganglion contained very low quantities of the peptide. These results suggest that (1) somatostatin may function as a neurotransmitter in the NTS and (2) the somatostatin-containing innervation of the NTS is at least in part from extrinsic neurons located in the lower brainstem and not from vagal afferent or forebrain neurons.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000378:metabolism*; D013116:Spinal Cord / Q000502:physiology; D014278:Trigeminal Nuclei / Q000502:physiology
D013004:Somatostatin; D004533:Egtazic Acid; D011188:Potassium; D002118:Calcium