Journal Article Increased 45Ca-efflux from smooth muscle microsomes by a rise in an extramicrosomal Ca ion concentration, and the effect of thymol Get access Tetsuhiro Hisayama, Tetsuhiro Hisayama Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Miyama, Funabashi, Chiba 274, Japan Search for other works by this author on: Oxford Academic Google Scholar Issei Takayanagi Issei Takayanagi Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Miyama, Funabashi, Chiba 274, Japan Correspondence. Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Miyama, Funabashi, Chiba 274, Japan Search for other works by this author on: Oxford Academic Google Scholar Journal of Pharmacy and Pharmacology, Volume 35, Issue 8, August 1983, Pages 532–533, https://doi.org/10.1111/j.2042-7158.1983.tb04828.x Published: 12 April 2011 Article history Received: 28 October 1982 Published: 12 April 2011
The beta-adrenergic action is thought to be related to the ability of the beta-adrenergic stimulants to increase the intracellular level of cyclic adenosine 3’,5’-monophosphate (cyclic AMP) in the smooth muscle (1). Recently some workers (2,3) have mentioned that papaverine, a smooth muscle relaxant, is found to strongly inhibit cyclic phosphodiesterase in rabbit aorta and rat uterus. On the other hand, Takagi, Takayanagi and Tomiyama (4, 5) have reported that the relaxing effects of papaverine and isoprenaline, a beta-adrenergic stimulant, are identical to exogenous dibutyryl cyclic AMP and that these drugs suppress a supply of calcium to the contractile protein at the membrane, Further, Takagi, Takayanagi and Tsuchida (6) have also indicated using the taenia from the guinea pig caecum that caffeine and imidazole, which influence phosphodiesterase activity, considerably modify the responses of the taenia to isoprenaline and papaverine, while the action of phenylephrine, an alpha-adrenergic stimulant, is slightly affected by caffeine and imidazole. These results indicate the possibilities that the actions of beta-adrenergic stimulants and papaverine are mediated through an increase of the intracellular level of cyclic AMP and that cyclic AMP is not concerned with the response to alpha-adrenergic stimulants.
Fullerence (C60) was determined by high-performance liquid chromatography using both ultraviolet and mass spectrometric detection. The detection limit for each method was 0.05 and 2.0 ng (signal-to-noise ratio (S/N = 2)) per injection, respectively. Rat plasma spiked with C60 (10 micrograms/ml) was extracted using solid phase extraction with a recovery of 62.1% and the coefficient of variation (c.v., n = 5) between intra-day assays was 4.0%. The calibration curve for peak area and plasma C60 concentration with ultraviolet detection showed good linearity (r = 0.996) over the range 0.5-60 micrograms/ml. This newly developed method was applied to rat plasma samples after intravenous administration of C60 solubilized with polyvinylpyrrolidone.
Some ergot alkaloids relaxed catch contraction of an isolated molluscan smooth muscle (anterior byssus retractor muscle of Mytilus edulis). Haloperidol, a competitive dopamine antagonist, shifted the dose response curves of ergot alkaloids, but methysergide did not. Bromocriptine, a potent dopaminergic ergot alkaloid, did not relax catch contraction. These results suggest that relaxation of catch contraction by some ergot alkaloids is mediated through dopamine receptors of this muscle, but dopamine receptors of this muscle seem to be somewhat different from those of mammalian brain.
Pentanoylcholine iodide and n-hexyltrimethylammonium bromide were muscarinic partial agonists in a sphincter pupillae muscle of rabbit as well as intestinal smooth muscles. Both partial agonists behaved as mydriatics in a constricted pupil and as miotics in a dilated pupil.
