Brainstem localization of a thyrotropin-releasing hormone-induced change in respiratory function.
When rats received microinjections of 100 ng thyrotropin-releasing hormone (TRH) into the medial portions of the nucleus tractus solitarius and 12th nucleus or raphe obscurus, at the level of the obex, a significant decrease in the inspiratory time was found. Examination of TRH immunocytochemistry revealed a high density of TRH-positive nerve terminals in these regions, especially the more caudal aspects. If serotonin was depleted by neonatal 5,7-dihydroxytryptamine treatment, the respiratory response of the adults to TRH appeared potentiated. Even though the neonatal 5,7-dihydroxytryptamine reduces the occurrence of TRH-positive cell bodies, TRH-positive fibers were not appreciably altered. These results are discussed with regard to a possible role of endogenous TRH in the brainstem on rhythmic respiratory activity.
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D001931:Brain Mapping; D001933:Brain Stem / Q000187:drug effects*; D005260:Female; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects; D011903:Raphe Nuclei / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration / Q000187:drug effects*; D012701:Serotonin / Q000502:physiology; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism / Q000494:pharmacology*
D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D013973:Thyrotropin-Releasing Hormone