AJP - Heart and Circulatory Physiology, Vol 249, Issue 4 876-H882, Copyright © 1985 by American Physiological Society
Innervation of bat heart: cholinergic and adrenergic nerves innervate all chambers
J. E. O'Shea and B. K. Evans
Adult Miniopterus schreibersii were anesthetized with chloroform, and in
vitro preparations of cardiac chambers were prepared. Stimulation of
intramural nerves in right ventricles paced at 6 Hz caused an inhibition
(56.3 +/- 3.5% decrease on basal force) mediated by cholinergic nerves and
an excitation (91.5 +/- 9.9% increase on basal force) mediated by
adrenergic nerves. Mean pD2s (-log effective concentration, 50%) for
ventricular beta-adrenoceptors and muscarinic cholinoceptors were 6.99 +/-
0.03 and 6.42 +/- 0.07, respectively. The inhibition of ventricular
contractility, by nerve stimulation or exogenous acetylcholine, occurred
even after blockade of beta-adrenoceptors. The results were comparable to
those obtained on atria. In some experiments, the heart was perfused in
situ and paced via electrodes on the ventricle: stimulation of the right
vagus nerve decreased right ventricular contractility by up to 90%. The
results show that, at least in this hibernating mammal, there is an
adrenergic innervation of the ventricle. The presence of a cholinergic
vagal innervation capable of inhibiting the basal force of ventricular
contraction has not been shown in any other mammal.
