Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:58-74-2 (Papaverine)
 470 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, intracavernous injection of some vasoactive drugs has been performed for the diagnosis and treatment of impotence. Despite extensive studies the mechanism of erection is still obscure. Therefore, the author studied the effects of some vasoactive drugs on isolated rabbit corpus cavernosum penis. Norepinephrine, phenylephrine or clonidine caused contraction of isolated rabbit corpus cavernosum strips in a concentration-dependent manner. This contractile effect was more potent with norepinephrine and phenylephrine than with clonidine. Prazosin was more effective than yohimbine in inhibiting norepinephrine-induced contractions. Papaverine and verapamil strongly relaxed the strips contracted by norepinephrine. Prostaglandin E1 also showed a relaxant effect. Low concentrations of isoproterenol caused relaxation, but in high concentrations it caused contraction. Acetylcholine relaxed norepinephrine-contracted strips in a concentration-dependent manner. Although the relaxant effect of acetylcholine was weaker than that of papaverine at high concentrations, acetylcholine and papaverine were almost equally effective at low concentrations. Vasoactive intestinal polypeptide relaxed the strips, and it was significantly more potent than papaverine. These findings suggest that both postsynaptic alpha 1-adrenoceptors and alpha 2-adrenoceptors are present in rabbit corpus cavernosum penis, and that alpha 1-adrenoceptors are predominant. The flaccid state of the rabbit penis seems to be maintained mainly by alpha 1-adrenoceptors. Verapamil seems to be useful for the diagnosis and treatment of impotence as papaverine. Acetylcholine and vasoactive intestinal polypeptide may be neurotransmitters involved in erection.
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PMID:[Effects of vasoactive drugs on isolated rabbit corpus cavernosum penis]. 255 73

The influence of Ca-antagonists and antispasmodic drugs on contractions by ACh and by DMPP were investigated. Verapamil (10(-5) to 10(-4) M), diltiazem (10(-5) to 10(-4) M) and D-600 (10(-5) to 10(-4) M) depressed both the contractions in a dose dependent manner. Papaverine (10(-5) to 10(-4) M) and Aspaminol (10(-6) to 10(-5) M) also depressed both the contractions in a dose dependent manner. These findings indicate that Ca2+, which initiates the contraction by ACh, is supplied from both the external medium and intracellular store sites.
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PMID:Effects of Ca-antagonists and antispasmodic drugs on contraction by ACh in molluscan smooth muscle. 285 40

Urotensin II (U II) caused marked concentration-dependent contractions of helical strips from several major arteries of the rat. The thoracic aorta was most sensitive; the apparent concentration of U II producing half-maximal contraction was 6.8 X 10(-10) M. Papaverine, dibutyryl cyclic AMP, forskolin, and nitroprusside antagonized the contractile responses to U II at the apparent concentrations producing 50% inhibition (IC50) of 7.6 X 10(-6), 2.1 X 10(-4), 2.5 X 10(-6), and 1.5 X 10(-8) M, respectively. Verapamil, a calcium channel-blocking agent, partially inhibited the contractile response to U II at IC50 = 6.5 X 10(-6) M. Maximal relaxation, i.e., a complete inhibition, could not be obtained even at a concentration of 3 X 10(-5) M verapamil. Cyproheptadine reduced the U II-induced contraction at higher concentrations. Phentolamine (10(-5) M), propranolol (10(-5) M), atropine (10(-4) M), tetrodotoxin (10(-6) M), burimamide (10(-5) M), and indomethacin (10(-5) M) did not change the U II-induced contraction. At higher concentration, U II (10(-8) M) induced a small contraction of aortic strips in Ca2+-free Krebs Henseleit solution similar to that of norepinephrine, but the U II-induced contraction was not inhibited by phentolamine or propranolol. The action of U II did not require the presence of endothelial cells. It is concluded that U II acts on vascular smooth muscle and induces the contraction partly through intracellular Ca2+ mobilization but mainly by stimulating the influx of extracellular Ca2+ via potential dependent and potential independent calcium channels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Contraction of major artery segments of rat by fish neuropeptide urotensin II. 381 73

Procaine (1 X 10(-5)-1 X 10(-4) M), dibucaine (1 X 10(-5)-1 X 10(-4) M) and tetracaine (1 X 10(-6)-1 X 10(-5) M) caused an increase followed by a decrease in the rate of spontaneous afferent (A) discharges (D) accompanied with a decrease in the flow rate of perfusion solution from the pulmonary vein in the isolated lung of the bullfrog, but these local anesthetics only decreased the rate of A.D. synchronized with lung inflation. The stimulatory effects of these drugs on the rate of spontaneous A.D. were studied. In the presence of TTX (1 X 10(-7) M), the increase in the rate of spontaneous A.D. by local anesthetics was inhibited, but the decrease in the flow rate of perfusion solution by these drugs was not inhibited. Papaverine (1 X 10(-5) M), which inhibited the decrease in the flow rate of perfusion solution by these local anesthetics, inhibited the increase in the rate of spontaneous A.D. by dibucaine, but not those by procaine and tetracaine. The inhibitory effects on the increase in the rate of spontaneous A.D. by these local anesthetics could be seen with verapamil in a concentration (1 X 10(-4) M) which significantly inhibited the rate of spontaneous A.D., like TTX (1 X 10(-7) M). Verapamil could not reverse the decrease in the flow rate of perfusion solution by these local anesthetics. From these result, the increase in the rate of spontaneous A.D. by procaine and tetracaine is due to not only the contractile effects of the drugs on the pulmonary vessel but also the direct stimulatory effects on the receptors which generate spontaneous A.D., and the increase in the rate of spontaneous A.D. by dibucaine may result from the contraction of the pulmonary vessel, and the stimulatory effect of dibucaine on the receptors would be weaker than that of procaine and tetracaine, since dibucaine could cause the increase in the rate of spontaneous A.D. only when dibucaine decreased the flow rate of perfusion solution.
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PMID:The effects of tetrodotoxin, papaverine and verapamil on the increase in the rate of spontaneous afferent discharges induced by local anesthetics from the pulmonary mechanoreceptors of the bullfrog. 387 56

The effects of some vasodilators on the mobilization of different Ca2+ pools during contractions produced by noradrenaline and high K+ medium in rabbit ear artery has been investigated. Sodium nitrite was much more effective in antagonizing high K+-stimulated Ca2+ fluxes through the potential-dependent Ca2+ channels than noradrenaline-induced mobilization of intracellular Ca2+ stores or Ca2+ fluxes through receptor-operated channels. Papaverine was only slightly more active on contractions sustained by influx of extracellular Ca2+ (through potential-dependent channels and receptor-operated channels) than on those sustained by intracellular Ca2+. Verapamil and nifedipine were much more effective in antagonizing contractions sustained by Ca2+ entry through potential-dependent channels than through receptor-operated channels. Nifedipine was completely ineffective in antagonizing noradrenaline-induced mobilization of intracellular Ca2+ stores while verapamil had a limited inhibitory action in high concentrations. Phentolamine was equieffective in antagonizing both types of noradrenaline-induced contractions while having no effect on high K+-induced tonic contraction.
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PMID:Differential effects of vasodilators on the mobilization of calcium pools during contractions of rabbit ear artery induced by noradrenaline and high potassium. 614 Dec 59

The effects of verapamil, papaverine and octylonium bromide on amplitude and frequency of spontaneous contractions of rabbit duodenum and rat colon, portal vein and right atria have been investigated. Myogenic nature of spontaneous contractions was demonstrated by their resistance to tetrodotoxin (100 micrograms/ml) and hexamethonium (10(-4) M). Verapamil (10(-7) - 5 X 10(-6) M) reduced, in a concentration-dependent manner, amplitude and frequency of spontaneous contractions with a certain degree of selectivity for duodenal preparations. Automaticity of rat right atria was affected by concentrations of verapamil higher than those required to modify automaticity of intestinal preparations. Papaverine (3 X 10(-6) - 3 X 10(-4) M), was almost equipotent in reducing the amplitude of spontaneous contractions of each preparation but inhibited the frequency of contractions in the following order: colon greater than duodenum greater than atrium. Octylonium bromide (10(-6) - 10(-4) M) was characterized by its greater effectiveness in reducing frequency and amplitude of spontaneous contractions of rat colon as compared to the other preparations. All three smooth muscle relaxant drugs, in spite of concentration-related reduction in amplitude, determined a parallel enhancement of frequency of spontaneous contractions in rat portal vein. Differences in drug selectivity are discussed in terms of different roles played by various Ca++-dependent processes (which constitute the cellular target of action of these smooth muscle relaxant drugs) in the genesis of frequency and amplitude of myogenic contractions in the various preparations.
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PMID:System and organ-selectivity of smooth muscle relaxants on in vitro spontaneously contracting preparations. 614 32

The effects of nitrendipine, a new antihypertensive agent, have been examined using the isolated rabbit aortic strip stimulated with either noradrenaline (1.7 X 10(-8) - 1.7 X 10(-5) mol/L) or potassium (22.7-52.7 mmol/L). Nifedipine, verapamil, phentolamine, papaverine, and minoxidil were used as reference compounds. Nitrendipine and nifedipine had little effect on the contractions of the aortic strip induced by noradrenaline, but concentration-dependently inhibited contractions induced by potassium depolarisation (IC50) (3.1 X 10(-9) and 8.1 X 10(-9) mol/L, respectively). Verapamil had little effect on contractions induced by the highest concentration of noradrenaline (1.7 X 10(-5) mol/L) but inhibited contractions induced by lower concentrations of noradrenaline. Potassium-induced contractions were inhibited with an IC50 of 1.4 X 10(-7) mol/L. Phentolamine competitively inhibited noradrenaline-induced contractions, but had no effect on those induced by potassium. Papaverine inhibited both noradrenaline- and potassium-induced contractions with an IC50 of 2.5 X 10(-5) and 3 X 10(-5) mol/L, respectively. Minoxidil also inhibited both types of contractions, but only at very high concentrations (IC50 1.3 X 10(-3) and 1.8 X 10(-3) mol/L). I conclude that nitrendipine, like nifedipine, acts by inhibiting the depolarisation-induced influx of calcium ions into the vascular smooth muscle. There is no evidence for alpha-adrenoceptor-blocking activity, nor for papaverine-like vasodilator activity. Verapamil also appears to act by a calcium antagonistic action; but may, in addition, possess some alpha-adrenoceptor-blocking activity.
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PMID:Effects of nitrendipine (BAY e 5009), nifedipine, verapamil, phentolamine, papaverine, and minoxidil on contractions of isolated rabbit aortic smooth muscle. 618 80

On isolated rat vas deferens both papaverine and verapamil show a non competitive antagonism against norepinephrine and a competitive antagonism against Ca2+. Verapamil is nearly 100 times more active than papaverine. On the main pulmonary artery and on the thoracic aorta of the rabbit, verapamil shows a competitive antagonism against both norepinephrine and Ca2+ but it is more effective (almost 100 times) against Ca2+ than norepinephrine. Papaverine also shows a competitive antagonism against norepinephrine but a non competitive antagonism against Ca2+. The contrasting results obtained on rat vas deferens and rabbit vessels might be due to: 1) mechanism(s) of action of the agonist; 2) properties of the biological object as far concerns receptor activation and mechanism(s) of excitation-contraction coupling; 3) mechanism(s) of action of spasmolytic drugs. All these factors act in a cooperative way in determining the quality and the quantity of the observed responses.
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PMID:Action of papaverine and verapamil on norepinephrine and calcium evoked contraction of vascular and non vascular smooth muscle. 633 40

The effects of papaverine and verapamil were studied in spontaneously beating right atria of guinea pigs, rabbits and rats and on segments of sinoatrial node tissue from rabbits. Papaverine (10(-4)M) produced a significant negative chronotropic effect in guinea pigs and rats, with a lesser effect in rabbits. Papaverine antagonized the positive chronotropic response to transmural nerve stimulation (TNS) of the sinoatrial node of rabbit atria in a concentration-dependent manner. The chronotropic response to 5 X 10(-7)M norepinephrine was enhanced in the presence of 10(-6)M papaverine, but was noncompetitively antagonized at concentrations above 10(-5)M. The negative chronotropic response to TNS was unaltered by papaverine except at concentrations at or above 5 X 10(-5)M; however, the negative chronotropic response to 5 X 10(-6)M methacholine was not altered by 10(-4)M papaverine. A local anesthetic (lidocaine) inhibited both the positive and negative chronotropic TNS response at a concentration that had no effect on the response to exogenous norepinephrine. Verapamil (10(-7) to 10(-6)M) had no significant effect on either the positive or negative chronotropic response to TNS. The effects of papaverine on TNS are attributed to the influence of at least three actions: 1) phosphodiesterase inhibition, 2) local anesthetic activity and 3) physiological antagonism of norepinephrine. The effects of 2 X 10(-4)M papaverine on action potentials of rabbit sinoatrial node cells were studied. Papaverine decreased the maximum diastolic potential, increased the action potential overshoot and transformed the normal ramp configuration of slow diastolic depolarization into a concave shape.
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PMID:Influence of papaverine on spontaneous activity of isolated right atria from small mammals. 636 76

The suppression of the Ca spike frequency generated spontaneously in the guinea-pig taenia coli was quantitatively investigated using the single sucrose gap method in an attempt to correlate frequency with the relaxation induced by Ca antagonists, isoproterenol and papaverine. The intrinsic activity (a) of depleted Ca that gave the maximal response in the dose-spike frequency curve (DSfC) or dose-tension curve (DTC) was taken as unity. Verapamil and MnCl2: a of both the DSfC and DTC were 1.0. Papaverine: a of the DSfC was 0.5 in contrast to 1.0 in the case of the DTC, and the affinity of the DSfC was somewhat less than that of the DTC. Isoproterenol: a and affinity of the DSfC were considerably less than in the case of the DTC. These results indicate that (1) relaxation induced by the Ca antagonists we used clearly corresponded to the suppression of the Ca influx carrying the action potential, (2) the relaxation induced by isoproterenol was not due to direct suppression of Ca influx, and (3) papaverine and depleted Ca influenced Ca both directly and indirectly.U
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PMID:Quantitization of Ca spike frequency in a single sucrose gap and mechanical relaxation induced by Ca antagonists, isoproterenol and papaverine. 730 51


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