Investigation of the vagally induced changes in transmural potential difference in the ferret jejunum in vivo.
This study was designed to determine whether the non-cholinergic, non-adrenergic rise in transmural potential difference (PD), induced by vagal nerve stimulation is an efferent effect or one caused by the antidromic stimulation of afferent fibers. Unilateral left supranodose vagotomy was performed, which caused degeneration of efferent fibers within the vagus nerve, leaving the nodose ganglion, and consequently afferent cell bodies, undamaged. After stimulating the unoperated nerve there was an increase in jejunal motility, a rise in transmural PD and a fall in systemic blood pressure. Although cholinergic blockade with atropine and adrenergic blockade with or a combination of phentolamine and propranolol abolished this vagally induced motor activity and fall in systemic blood pressure, the transmural PD response induced by stimulation of the unoperated nerve was only partially inhibited. However, the subsequent administration of the nicotinic ganglionic blocker, hexamethonium, abolished this transmural PD response. In contrast, stimulation of the operated vagus nerve failed to produce these effects. Therefore, cholinergic and non-cholinergic efferent fibers are responsible for the vagally induced rise in transmural PD and thus fluid secretion in the ferret jejunum.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure; D002799:Cholinergic Fibers / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D005289:Ferrets; D005769:Gastrointestinal Motility; D007583:Jejunum / Q000294:innervation* / Q000502:physiology; D008297:Male; D008564:Membrane Potentials; D009431:Neural Conduction; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*
D001285:Atropine