Effects of alverine on the spontaneous electrical activity and nervous control of the proximal colon of the rabbit.

To analyse the mechanisms of the antispasmodic action of alverine, the effects of this drug on the spontaneous motility and nervous control of the proximal colon of the rabbit were studied in vivo. The electrical activity of the colonic smooth muscle was recorded using extracellular electrodes. The parasympathetic efferents were activated by electrical stimulation of distal ends of the vagus nerves. Alverine given intravenously inhibits spike potentials without modifying the slow waves. Excitatory and inhibitory responses induced by parasympathetic efferent stimulations, as well as the hyperpolarization due to intraluminal distension, were also blocked after drug injection. Our results show that alverine is able to block the spontaneous contractions and the nervous control of rabbit proximal colon, indicating that this drug has powerful antispasmodic effects.