Effects of pinaverium bromide and verapamil on the motility of the rat isolated colon

Abstract

Pinaverium bromide was 30 times less potent than verapamil in inhibiting intraluminal pressure responses of in vitro rat colonic segments to barium chloride, acetylcholine, FK 33–824 or field stimulation. The inhibitory effects of both verapamil and pinaverium bromide on the pressure responses to field stimulation were antagonized similarly by exogenous calcium administration. These results support the concept that pinaverium bromide acts on calcium channels in the smooth muscle cell membrane.

Effects of calcium channel blockers on gastric emptying and acid secretion of the rat in vivo

“…This fact, together with the antagonistic actions on calcium channel exhibited in other tissues of the rat in vivo by similar doses of verapamil (Curtis et al, 1984) clearly imply that the delay in gastric emptying is due to calcium antagonist effects. Our results are in keeping with previous studies describing similar inhibitory effects of these drugs, both in vivo and in vitro, on smooth muscle from other parts of the mammalian gastrointestinal tract such as the oesophagus (Goyal & Rattan, 1980;Hongo et al, 1984;Morales-Olivas et al, 1985) or the colon (Blume et al, 1983;Baumgartner et al, 1985). Although recently Ogle et al (1985) observed that verapamil did not affect the gastric emptying of solids, the low doses used by these authors could account for this difference.…”

Interaction of pinaverium (a quaternary ammonium compound) with 1,4‐dihydropyridine binding sites in rat ileum smooth muscle

“…Earlier studies on smooth muscle tissue suggest that pinaverium exerts its spasmolytic action mainly by blocking voltage-dependent Ca2+ channels and has little effect on receptor-operated channels and intracellular Ca2+ stores (Droogmans et al, 1983;Baumgartner et al, 1985;Beech et al, 1990). Its selectivity for the intestinal tract is attributable to its low absorption by the gut and its marked hepatobiliary excretion (Jacquot et al, 1989).…”

Effects of pinaverium on voltage‐activated calcium channel currents of single smooth muscle cells isolated from the longitudinal muscle of the rabbit jejunum

“…In experiments on isolated smooth muscle preparations, pinaverium inhibited contractions of intestinal muscle to nerve stimulation, barium chloride and acetylcholine. The inhibition was non-competitive and was antagonized by increasing the calcium concentration of the bathing solution (Bretaudeau & Foussard-Blanpin, 1980;Baumgartner et al, 1985). However, pinaverium has little blocking activity at muscarinic receptors (Bretaudeau et al, 1975) suggesting that its spasmolytic action is exerted in some other way.…”