Dorsal medullary serotonin and gastric motility: enhancement of effects by thyrotropin-releasing hormone.
The effects of serotonin (5-HT) and thyrotropin-releasing hormone (TRH) on gastric motility patterns were investigated. Microinjection of serotonin (8 pmol in 4 nl) into the dorsal motor nucleus of the vagus produced a small increase in motility and tone, an effect which declined with repeated injections. As demonstrated previously, TRH (1 nmol in 1 microliter) applied to the surface of the dorsal medulla evoked a large increase in gastric motility and tone. After gastric motility returned to baseline following the TRH injection, we found that subsequent 5-HT injections, which previously evoked small changes in motility and tone, now evoked large increases in these indices. TRH augmentation of 5-HT-mediated effects on autonomic nuclei may be a significant feature in the alterations in gastric function that accompany the sleep-waking cycle and stress-related gastric pathology.
McCann
M J
MJ
Department of Physiology, Ohio State University College of Medicine, Columbus 43210.
Hermann
G E
GE
Rogers
R C
RC
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D012701:Serotonin / Q000494:pharmacology* / Q000502:physiology; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology*
D012701:Serotonin; D013973:Thyrotropin-Releasing Hormone; D001285:Atropine