Increased choline acetyltransferase activity in pressure-overloaded right ventricles of guinea pigs.

Choline acetyltransferase activity, a biochemical indication of parasympathetic innervation, is increased in the hypertrophied right ventricle of guinea pigs after pulmonary artery constriction (PAC). The increase appears to be dependent on the severity and the duration of hypertrophy. This change in choline acetyltransferase activity suggests compensatory changes occur in the parasympathetic innervation of PAC guinea pigs which allows the right ventricle to maintain its level of parasympathetic innervation despite marked hypertrophy. Unlike the right ventricle, the SA node of PAC guinea pigs does not have detectable changes in choline acetyltransferase activity. This model of right ventricular hypertrophy also does not have detectable changes in baroreflex control of heart rate.