[Comparison of the inhibitory effect of diltiazem on neurogenic contractions in the mesenteric arteries and veins].
The effect of diltiazem on the magnitude of isometric contractions induced by electric stimulation of intramural nerves (4Hz) was studied on isolated rings of the mesenteric artery and vein of the dog and rabbit. Diltiazem in concentrations of 10(-5) mol/l and above inhibited neurogenic contractions of the mesenteric artery and vein of the dog in a dose-dependent manner. Inhibition of contractions of the mesenteric vein was found to be more pronounced than that of contractions of the mesenteric artery. In the mesenteric vessels of the rabbit, diltiazem in concentrations of 10(-6) and above inhibited neurogenic contractions, and again more markedly in the veins than in the arteries. On comparing the inhibition of contractions in the two animal species studied, the contractions of the mesenteric vein of the rabbit were found to be more intensely inhibited than those of the dog vein. Diltiazem inhibited also phentolamine-resistant neurogenic contractions of the mesenteric artery. The established differences in the magnitude of neurogenic contraction inhibition may presumably be accounted for by quantitative differences in adrenergic innervation of mesenteric arteries and veins, as well as by differences in the magnitude of the contraction component dependent on extracellular calcium which is greater in the veins than in the arteries. This may also explain the more pronounced inhibition of neurogenic contractions in the veins compared to arteries.
Török
J
J
Ustav normálnej a patologickej fyziológie SAV, Bratislava, CSFR.
Töröková
R
R
D000320:Adrenergic Fibers / Q000502:physiology; D000818:Animals; D003864:Depression, Chemical; D004110:Diltiazem / Q000494:pharmacology*; D004285:Dogs; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000294:innervation / Q000502:physiology*; D008642:Mesenteric Veins / Q000187:drug effects* / Q000294:innervation / Q000502:physiology*; D011817:Rabbits; D014661:Vasoconstriction / Q000187:drug effects*
D004110:Diltiazem