A functional study of the development of the cardiac sympathetic neuroeffector junction in the shr

Abstract

We studied the function of the cardiac sympathetic nerve varicosity in isolated right atrial preparations of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats at 4, 9, 14, 20 and 50 weeks of age. Cumulative concentration-atrial period response (C-R) curves to isoprenaline showed similar maximum response and sensitivity (EC50) at all ages but there was an age-related fall in resting atrial rate. Similar results were found for methox- amine (α1-adrenoceptor agonist) although the maximum response was significantly less than for Isoprenaline. The time-dependent recovery (T1/2) of the fall in atrial period in response to sympathetic nerve stimulation from electrical field pulses (..