BLOCKADE OF SUPERIOR CERVICAL GANGLIONIC TRANSMISSION BY TROPINE-P-TOLYLACETATE AND ITS QUATERNARY METHIODIDE DERIVATIVE

The in vivo cat superior cervical ganglion (G) preparation was used in a study of ganglionic blockade evoked by the tertiary ester tropine-p-tolylacetate(II) and its quaternary methiodide derivative (I), singly and in mixtures. It was observed that the individual potency indexes for induction of blockade fell in the strength sequence I > II, that sensitivity of the ganglionic tissues to blockade by these esters was less than that of phrenic nerve-diaphragm tissues, and that quaternary I and tertiary II engaged in a strong antagonism at ganglionic receptors. The extent of the antagonism increased with total concentration level of ester mixtures reaching the ganglion and was fairly independent of the I:II ratio at any given total concentration of injected ester mixture. The antagonism phenomenon was examined in terms of possible mechanisms underlying the reversible blocking interactions of the two esters with G tissue receptor systems. © 1969.