Nicotine-like effect of prostaglandin F2alpha on longitudinal smooth muscle of cat jejunum.

The effect of hexamethonium (1 x 10(-6) M) chlorpromazine (1 x 10(-6) M) and physostigmine (1 x 10(-7) M) on the spastic effects of PGF2alpha (3 x 10(-7) M), PGE1 (3 x 10(-7) M) acetylcholine (1 x 10(-8) M) and nicotine (1 x 10(-7) M), was studied on isolated longitudinal smooth muscle of cat jejunum. The contractile effects of PGF2alpha and nicotine were found to decrease on an analogous scale as a result of hexamethonium and chlorpromasine administration and to be potentiated by physostigmine. Hexamethonium and chorpromazine do not influence significantly the spastic effects of acetylcholine, physostigmine potentiates them less markedly. Hexamethonium reduces whereas physostigmine and chlorpromazine potentiate the contractile effect of PGE1. Taking into consideration also the results of previous studies (Petkov, Radomirov, 1977), it is assumed that the contractile effect of PGF2chi on the longitudinal muscle of cat jejunum is at least partly mediated through ganglionic stimulation, i.e. the mechanism of the spastic action of PGF2chi on the smooth muscle used has at least partly a nicotine-like character.