Serotonin modulates nicotinic responses of adrenal chromaffin cells.
5-Hydroxytryptamine (5-HT) specifically and reversibly inhibits nicotine-induced currents and catecholamine release in bovine adrenal chromaffin cells in culture. Pharmacological analysis indicates that the inhibition is not mediated by known 5-HT receptor subtypes. The inhibition is noncompetitive over a range of nicotine concentrations between 1 and 100 microM. Preincubation with either 5-HT or substance P significantly protects the response from nicotine-induced desensitization. It is concluded that 5-HT inhibits nicotinic acetylcholine receptors on bovine adrenal chromaffin cells, probably by binding to a noncompetitive site on the receptor itself. Because both blood and the chromaffin cells contain 5-HT, the inhibition provides an opportunity for negative control of catecholamine secretion from the adrenals.
Vijayaraghavan
S
S
Department of Biology, University of California, San Diego, La Jolla 92093-0322.
Schmid
H A
HA
Mapp
K S
KS
D000311:Adrenal Glands / Q000166:cytology / Q000187:drug effects*; D000818:Animals; D002838:Chromaffin System / Q000166:cytology / Q000187:drug effects*; D009538:Nicotine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009638:Norepinephrine / Q000037:antagonists & inhibitors; D009994:Osmolar Concentration; D011985:Receptors, Serotonin / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology*; D013997:Time Factors
D011985:Receptors, Serotonin; D012701:Serotonin; D009538:Nicotine; D009638:Norepinephrine