Selective adrenergic stimulant actions of 1-isopropylamino-3- (2-thiazoloxy)-2-propanol (ITP) in anesthetized cats

Lockwood, Raymond H.; Lum, Bert K. B.

doi:10.1016/0024-3205(74)90247-1

Cited by 18 publications

(4 citation statements)

References 12 publications

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“…Selective 01-agonists are more uncommon but a few examples exist. Increases in rate and force of cardiac contraction with little effect upon vascular P-adrenoreceptors have been reported in anaesthetized cat and dog for the 0-adrenoreceptor stimulant ITP (tazolol) (Roszkowski, Strosberg, Miller, Edwards, Berkoz, Lewis, Halpern & Fried, 1972;Lockwood & Lum, 1974), although in these laboratories (Lumley, 1980) and elsewhere (Clark & Poyser, 1977) it appears t o be an extremely weak agonist on isolated atria. Another agonist exhibiting selectivity for the 0-adrenoreceptors of cardiac, rather than uterine and lung preparations, is R0363, in which an oxymethylene group is inserted between the catecholamine ring and the ethanolamine side chain (Iakovidis, Malta, McPherson & Raper, 1980).…”

Section: Positive Inotropic and Chronotropic Responsesmentioning

confidence: 95%

Cardiac Adrenoreceptors

Broadley

1982

Journal of Autonomic Pharmacology

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Section: Positive Inotropic and Chronotropic Responsesmentioning

confidence: 95%

Cardiac Adrenoreceptors

Broadley

1982

Journal of Autonomic Pharmacology

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“…Metabolic responses to adrenaline and isoprenaline have also been compared with those produced by selective non-catecholamine agonists. Tazolol, or ITP, selectively produces cardiostimulation (Strosberg & Roszkowski, 1972); this agonist increases plasma FFA but does not increase glucose or lactate (Lockwood & Lum, 1974). Tazolol is therefore a presumably P, selective agonist which supports the Lands' classification of,i-adrenoceptors.…”

Section: Introductionmentioning

confidence: 84%

Differentiation of Metabolic Adrenoceptors

Loakpradit

Lockwood

1977

British J Pharmacology

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Cardiovascular and metabolic responses to intravenous infusion of isoprenaline were measured in fasted, anaesthetized cats. Isoprenaline (0.2 μg kg−1 min−1 for 15 min) decreased diastolic blood pressure and increased heart rate, blood glucose, blood lactate and plasma free fatty acids. Oxprenolol (0.5 mg/kg) antagonized all cardiovascular and metabolic effects of isoprenaline non‐selectively. Para‐oxprenolol (0.25 mg/kg) and practolol (4 mg/kg) antagonized the effects of isoprenaline on heart rate and free fatty acids selectively. H 35/25 ((1‐(4‐methylphenyl)‐2‐isopropyl aminopropanol) hydrochloride, 3 mg/kg) antagonized the effects of isoprenaline on blood pressure, glucose and lactate selectively. It is concluded that metabolic adrenoceptors are differentiated into subtypes similar to those mediating cardiostimulation and vasodilatation.

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“…Furthermore tazolol and H 80/62 induced vasodilatation in adipose tissue but not in the gracilis muscle. Both tazolol (Lockwood and Lum 1974) and H 80/62 (Hedberg et al 1977) has been shown to have PI-selective agonistic properties. Thus, the present study supports the view that vascular p-adrenoceptors in adipose tissue, in contrast to skeletal muscle, are mainly of the P1-type.…”

Section: Discussionmentioning

confidence: 99%

Comparison of β‐adrenoceptors mediating vasodilatation in canine subcutaneous adipose tissue and skeletal muscle

Belfrage

1978

Acta Physiologica Scandinavica

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Blood flow changes in response to various drugs in simulataneously autoperfused canine subcutaneous adipose tissue and gracilis muscle were compared to study the vascular beta-adrenoceptors. Compared to isoprenaline the beta 2-selective agonist salbutamol was 4--6 times more potent as a vasodilator in the muscle than in adipose tissue. Furthermore two beta 1-selective agonists (Tazolol and H80/62) caused vasodilatation in adipose tissue but not in the gracilis muscle. When given by close i.a. injection after beta-adrenoceptor blockade, adrenaline was a more potent vasoconstrictor than noradrenaline in both tissues. Before beta-blockade, however, noradrenaline was the more potent vasoconstrictor in the gracilis muscle whereas adrenaline was more potent in adipose tissue. Intravenous infusion of adrenaline in doses causing vasodilatation in the muscle caused vasoconstriction in adipose tissue whereas intravenous infusion of noradrenaline caused vasoconstriction in both tissues. The present findings suggest that the beta-adrenoceptors mediating vasodilatation in skeletal muscle are mainly ose tissue. Since adrenaline is a much more potent beta2- than beta1-agonist, these differences point to different roles of intravascular adrenaline in the two sites. In skeletal muscle circulating adrenaline is mainly a vasodilator whereas in subcutaneous adipose tissue it mainly acts as a vasoconstrictor.

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Selective adrenergic stimulant actions of 1-isopropylamino-3- (2-thiazoloxy)-2-propanol (ITP) in anesthetized cats

Cited by 18 publications

References 12 publications

Cardiac Adrenoreceptors

Cardiac Adrenoreceptors

Differentiation of Metabolic Adrenoceptors

Comparison of β‐adrenoceptors mediating vasodilatation in canine subcutaneous adipose tissue and skeletal muscle

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