Effect of various pharmacological agonists on the rat caecum-appendix preparation: a preliminary study.

A preliminary study with various pharmacological agents revealed the presence of contractile muscarinic and H1-histamine receptors as well as inhibitory alpha- and beta-adrenoceptors and purinoceptors in rat caecum-appendix. Histamine also produced indirect actions mediated through the release of catecholamines. 5-Hydroxytryptamine produced variable response, the contractile response was mediated through 5-HT receptors and the relaxant response through the release of catecholamines.