The nature of the vascular response to acetylcholine is tissue and species specific. Acetylcholine produces vasoconstriction in the pulmonary vasculature of rabbits and dogs and cycloxygenase inhibitors totally prevent or potentiate the response, respectively. The feline and bovine pulmonary vasculatures relax in response to actylcholine as do systemic vasculatures in all species tested. Acetylcholineinduced relaxation of many, but not all, vessels is mediated through the release of endothelium derived relaxing factor(s). Preliminary studies in our laboratory have uncovered differences in inhibition by muscarinic receptor subtype selective antagonists of the response to acetylcholine among vessels of different size and origin. Furthermore, we have demonstrated the existence and began characterizing muscarinic binding sites on bovine pulmonary arterial endothelial in culture. The proposed investigation will test the hypothesis that the localization, density, subtype or transduction mechanisms of endothelial or smooth muscle muscarinic receptors is different in vessels of different size and origin (bed or species). We propose to employ muscarinic receptor subtypeselective antogonists (pirenzepine, gallamine, secoverine, trihexiphenidyl, 4DAMP) to systematically characterize pulmonary and systemic endothelial and smooth muscle cell muscarinic receptors and their association with the activation of possible messengers (arachidonate metabolites, cyclic nucleotides, endothelium derived relaxing factor, inositol phosphate turnover, calcium influx). We will correlate receptor properties to type and amounts of messengers activated, in fresh isolates and cultures of endothelial and smooth muscle cells from large and small pulmonary artery, large and small pulmonary vein, aorta and mesenteric artery of rabbit, small pulmonary artery of cat and dog, vessels chosen for their diverse response to muscarinic stimulation. We will also correlate second messenger production in the different cell lines to the physiological response of the vessel in order to reveal possible selectivity of the biochemical pathways for each response.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL035953-03
Application #
3350419
Study Section
Experimental Cardiovascular Sciences Study Section (ECS)
Project Start
1987-07-01
Project End
1991-06-30
Budget Start
1989-07-01
Budget End
1991-06-30
Support Year
3
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Medical College of Georgia (MCG)
Department
Type
Schools of Medicine
DUNS #
City
Augusta
State
GA
Country
United States
Zip Code
30912
Aronstam, R S; Ryan, U S; Catravas, J D (1992) Muscarinic binding sites on bovine pulmonary arterial endothelial cells in culture. Pharmacology 44:324-33
Marczin, N; Ryan, U S; Catravas, J D (1992) Effects of oxidant stress on endothelium-derived relaxing factor-induced and nitrovasodilator-induced cGMP accumulation in vascular cells in culture. Circ Res 70:326-40
Marczin, N; Ryan, U S; Catravas, J D (1992) Methylene blue inhibits nitrovasodilator- and endothelium-derived relaxing factor-induced cyclic GMP accumulation in cultured pulmonary arterial smooth muscle cells via generation of superoxide anion. J Pharmacol Exp Ther 263:170-9
Marczin, N; Ryan, U S; Catravas, J D (1992) Endothelial cGMP does not regulate basal release of endothelium-derived relaxing factor in culture. Am J Physiol 263:L113-21
el-Kashef, H; Catravas, J D (1991) The nature of muscarinic receptor subtypes mediating pulmonary vasoconstriction in the rabbit. Pulm Pharmacol 4:8-19
el-Kashef, H A; Hofman, W F; Ehrhart, I C et al. (1991) Multiple muscarinic receptor subtypes in the canine pulmonary circulation. J Appl Physiol 71:2032-43
el-Kashef, H A; Catravas, J D (1990) Effects of arachidonic acid in the rabbit pulmonary and systemic vascular beds in vivo. Pharmacology 40:60-8
Legrand, A B; Narayanan, T K; Ryan, U S et al. (1990) Effects of adenosine and analogs on adenylate cyclase activity in cultured bovine aortic endothelial cells. Biochem Pharmacol 40:1103-9
Legrand, A B; Narayanan, T K; Ryan, U S et al. (1989) Modulation of adenylate cyclase activity in cultured bovine pulmonary arterial endothelial cells. Effects of adenosine and derivatives. Biochem Pharmacol 38:423-30