Interaction of some muscarinic agonists and antagonists at the prejunctional muscarinic receptor in the rabbit ear artery preparation

Choo, L. K.; Mitchelson, F.; Vong, Y.M.

doi:10.1111/j.1476-5381.1986.tb14591.x

Cited by 18 publications

(2 citation statements)

References 24 publications

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“…In many respects its activity resembles that of (4-(m-chlorophenylcarbamoyloxy)-2butynyl-trimethyl ammonium chloride) being 20 to 100 times less potent than the latter at ganglionic and peripheral sites (Jones, 1963; Trendelenburg, 1966;Jaramillo & Volle, 1967a,b;Fozard & Muscholl, 1972). However, differences exist between these two agonists in that is inactive at some receptors where McN-A-343 shows relatively high activity (Choo et al, 1986) and AHR-602 functions as an agonist at some sites where McN-A-343 acts as an antagonist (Brown et al, 1980).…”

Section: Introductionmentioning

confidence: 99%

Comparison of the effects of some muscarinic agonists on smooth muscle function and phosphatidylinositol turnover in the guinea‐pig taenia caeci

Gardner¹,

Choo²,

Mitchelson³

1988

British J Pharmacology

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Section: Introductionmentioning

confidence: 99%

Comparison of the effects of some muscarinic agonists on smooth muscle function and phosphatidylinositol turnover in the guinea‐pig taenia caeci

Gardner¹,

Choo²,

Mitchelson³

1988

British J Pharmacology

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“…In the rabbit ear artery the sympathetic nerves appear to have at least two types of inhibitory prejunctional muscarine receptors as a number of antagonists indicate different affinities for CCh and McN (Choo et al 1985(Choo et al , 1986Darroch et al 1990). For example pirenzepine was found to be approximately 20-fold more potent and AF-DX 116 three-fold less potent when McN rather than CCh was the agonist.…”

Section: Discussionmentioning

confidence: 99%

SELECTIVE INHIBITION OF RESPONSES TO CARBACHOL AND McN‐A‐343 IN THE RABBIT VAS DEFERENS

Choo¹,

Mitchelson²

1990

Clin Exp Pharma Physio

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1. The effect of several selective muscarine receptor antagonists were evaluated on the responses of carbachol (CCh) and McN-A-343 (McN) during sympathetic nerve stimulation in the rabbit vas deferens. 2. The muscarine M1 receptor antagonist pirenzepine exhibited similar apparent pKB values for antagonism of the prejunctional inhibitory response of either CCh (pKB, 8.2) or McN (pKB, 8.5) on sympathetic nerve stimulation. 3. The muscarine M2 receptor antagonists, pancuronium and the bisalkyl ammonium compound 'C7/3-phth' were selective inhibitors of the postjunctional facilitatory response produced by CCh on sympathetic nerve stimulation. They were also 17- and three-fold, respectively, less potent against the inhibitory responses of McN on sympathetic nerve stimulation. The apparent pKB value of pancuronium on the inhibitory response produced by CCh did not differ significantly (P greater than 0.05) from that using McN. A similar finding was made for C7/3-phth. 4. Selective blockade of the inhibitory response to CCh with pirenzepine (0.03 or 0.5 mumol/L) did not significantly (P greater than 0.05) modify the apparent pKB value for pancuronium on the facilitatory response of CCh. 5. Selective blockade of the facilitatory response to CCh with a low concentration of pancuronium (0.5 mumol/L) did not significantly (P greater than 0.05) modify the apparent pKB value for pancuronium (30 mumol/L) on the inhibitory response of CCh. 6. It is suggested that CCh and McN activate the same prejunctional M1 muscarine receptor and that pancuronium is the most selective of the muscarine M2 receptor antagonists presently tested in this preparation for distinguishing between muscarine M1 and M2 receptors.

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Prejunctional muscarine receptors in the rabbit ear artery differ from M1, M2 and M3 muscarine receptors

Darroch

Choo

Mitchelson

1992

Naunyn-Schmiedeberg's Arch Pharmacol

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The ability of several selective muscarine receptor antagonists to inhibit the effect of carbachol on prejunctional muscarine receptors on sympathetic nerve endings in the rabbit isolated ear artery was investigated to characterise the receptor subtype involved. Carbachol did not reduce responses to exogenous noradrenaline and the inhibitory effect of carbachol on responses to nerve stimulation was unaffected by hexamethonium (10 microM) indicating that the effect of the muscarine agonist was exerted prejunctionally and was not modulated by nicotine receptor stimulation. The dissociation constants or apparent dissociation constants obtained using (+/-)-benzhexol (pKB; 6.63), (R)-benzhexol methiodide (8.11), dicyclomine (5.86), (+/-)-telenzepine (7.34), AF-DX 116 (6.95), himbacine (7.60), (+/-)-hexahydrosiladiphenidol (5.39) and a bisquaternary ammonium compound, heptane-1,7-bis(dimethyl-3'-phthalimidopropyl ammonium bromide) (5.84), indicate that the muscarine receptor subtype involved is not of the M1, M2 or M3 subtype.

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Interaction of some muscarinic agonists and antagonists at the prejunctional muscarinic receptor in the rabbit ear artery preparation

Cited by 18 publications

References 24 publications

Comparison of the effects of some muscarinic agonists on smooth muscle function and phosphatidylinositol turnover in the guinea‐pig taenia caeci

Comparison of the effects of some muscarinic agonists on smooth muscle function and phosphatidylinositol turnover in the guinea‐pig taenia caeci

SELECTIVE INHIBITION OF RESPONSES TO CARBACHOL AND McN‐A‐343 IN THE RABBIT VAS DEFERENS

Prejunctional muscarine receptors in the rabbit ear artery differ from M1, M2 and M3 muscarine receptors

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