The Release of Intestinal Serotonin in Rats by Nicotine

Nicotine hydrogen tartrate, 100μg/kg of body weight, administered intravenously in rats produced a maximal depletion of total midjejunal serotonin stores (42%). This depletion was highly significant (P<0.001). Maximal depletion of serotonin stores in stomach fundus (SF), pyloric antrum (PA), midjejunum (MJ), and ascending colon (AC) mucosae after 100μg/kg of nicotine administered intravenously as a function of time were: SF, 43% at 15 seconds; PA, 41% at 20 seconds; MJ, 45% at 30 seconds; and AC, 34% at 15 seconds. The fall of these values was highly significant (P<0.001). Return to control values was apparent within 30 minutes. Equipotent doses of atropine sulfate and hexamethonium chloride blocked the nicotine response.