A Pharmacological Analysis of the Contractile Action of Histamine Upon the Ileal Region of the Isolated, Blood‐perfused Small Intestine of the Rat

Abstract

1 The mode of action of histamine was investigated on the rat isolated small intestine perfused at a fixed flow rate through the superior mesenteric artery with blood from the carotid artery of a heparinized donor rat. Compounds were closely injected into the superior mesenteric artery.2 Increasing doses (1 to 100 pg) of histamine caused a monophasic fast contraction of the i'eum.3 The fast contraction was abolished by tetrodotoxin, hexamethonium, morphine or mepyramine, but was not prevented by atropine. 4 The present study indicates that histamine produces the fast contraction of the ileum by primarily acting on the myenteric nerve plexus involving cholinergic interneurones.

Disturbance of the prejunctional modulation of cholinergic neurotransmission during chronic granulomatous inflammation of the mouse ileum

“…In the guinea‐pig small intestine, there is evidence that histamine H 3 receptors are involved in the presynaptic inhibition of cholinergic nerve activity ( Trzeciakowski, 1987 ; Tamura et al ., 1988 ; Poli et al ., 1991 ) but enteric synaptic transmission in this species is modulated by H 1 , H 2 and H 3 receptors ( Izzo et al ., 1998 ). Histamine acting on neuronal H 1 receptors also modulates cholinergic nerve activity in the myenteric plexus of the rat small intestine and in the cat stomach ( Sakai, 1979 ; Sim et al ., 1989 ). This suggests that histamine H 1 receptors may play a role in enteric cholinergic neurotransmission but that their role and importance may depend upon the species and tissue under study.…”