Chemoreceptors for serotonin (5-HT), acetylcholine (ACh), bradykinin (BK), histamine (H) and gamma-aminobutyric acid (GABA) on rabbit visceral afferent neurons.
The somata of type 'C' neurons in rabbit nodose ganglion are endowed with receptor sites for 5-HT, BK, ACh, II and GABA. 5-HT and ACh application to type 'C' neurons in the nodose ganglion of rabbits produced a rapid depolarization associated with an increased membrane conductance, most likely to Na+ and K+. BK and H elicited slow depolarizations accompanied by a decreased membrane conductance probably to K+. GABA induced a rapid depolarization associated with an increased conductance to Cl-. In contrast, type 'A' neurons were insensitive to the four algesic agents but responded to GABA. d-Tubocurarine or picrotoxin at relatively low concentrations blocked ACh, 5-HT and GABA depolarizations without affecting membrane properties. Hexamethonium blocked ACh responses but not 5-HT responses. In addition, no desensitization occurred between the substances 5-HT, ACh or BK. The results suggest that the depolarizing effect of these agents on visceral neurons might be exerted via different receptors.
D000109:Acetylcholine / Q000378:metabolism* / Q000494:pharmacology; D000344:Afferent Pathways / Q000502:physiology*; D000818:Animals; D001920:Bradykinin / Q000378:metabolism* / Q000494:pharmacology; D002628:Chemoreceptor Cells / Q000378:metabolism*; D006632:Histamine / Q000378:metabolism* / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009620:Nodose Ganglion / Q000502:physiology*; D011817:Rabbits; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology; D014403:Tubocurarine / Q000494:pharmacology; D014630:Vagus Nerve / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000494:pharmacology
D012701:Serotonin; D005680:gamma-Aminobutyric Acid; D006632:Histamine; D000109:Acetylcholine; D001920:Bradykinin; D014403:Tubocurarine