On the non-adrenergic, non-cholinergic innervation of the rainbow trout stomach

Abstract

1. The vagal innervation of the rainbow trout stomach has been studied in different preparations, including a “Loewi” preparation where the effluent from a perfused stomach was allowed to superfuse an isolated stomach wall strip preparation. 2. The major response to vagal stimulation is an inhibition of the stomach-wall muscle activity, followed by a pronounced rebound contraction. This effect is mediated by a non-adrenergic, non-cholinergic (NANC) innervation. 3. The NANC effect of vagal stimulation is diminished or abolished by ganglionic blockade, suggesting that the NANC neurons are postganglionic and enteric. 4. The effects of vagal stimulation on the perfused stomach are directly mimicked in an isolated stomach wall strip preparation superfused with the venous effluent from the stomach. This effect may be due to the presence of the NANC transmitter in the stomach perfusate after vagal stimulation.