Impaired inotropic responses to alpha-adrenergic stimulation in experimental left ventricular hypertrophy.

Fouad, Fetnat M.; Shimamatsu, Kazumasa; Hanna, Magdy M.; Khairallah, P A; Tarazi, Robert C.

doi:10.1161/01.cir.71.5.1023

Cited by 13 publications

(1 citation statement)

References 20 publications

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“…The development of cardiac or vascular hypertrophy leads to inconsistent changes in ventricular responses to phenylephrine. An increased responsiveness was shown in hyperthyroid rats (this study), with no change in noradrenalineinfused rats (Brown et al 1992) or in SHR (this study;Bohm et al 1988) and decreased responses in renal hypertensive rats (Fouad et al 1983) yet hypertrophy is common to these models.…”

Section: Discussionsupporting

confidence: 46%

Disease‐induced Changes in Α‐adrenoceptor‐mediated Cardiac and Vascular Responses in Rats

Brown

Amos

Miller

1994

Clin Exp Pharma Physio

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1. The physiological relevance of cardiac and vascular alpha-adrenoceptors may increase in disease states in which beta-adrenoceptors are altered. To test this, positive inotropic and vasoconstrictor responses to phenylephrine were measured in isolated tissues from rats with experimentally-induced hyperthyroidism, hypothyroidism and diabetes as well as in genetically spontaneous hypertensive rats (SHR). 2. In left atria, positive inotropic responses to phenylephrine were increased in hypothyroid and diabetic rats and abolished in hyperthyroid and SHR. 3. In contrast, phenylephrine produced increased positive inotropy in left ventricular papillary muscles from hyperthyroid rats, increased potency in diabetic rats and negative inotropic responses in hypothyroid rats. 4. The potency of phenylephrine as a vasoconstrictor in thoracic aortic rings was increased in hyperthyroid and SHR and decreased in hypothyroid rats. 5. Thus, disease states which alter beta-adrenoceptor responsiveness can independently regulate atrial, ventricular and vascular responses to the alpha 1-adrenoceptor agonist, phenylephrine. Therefore, these disease states may alter the physiological control of the cardiovascular system by noradrenaline and adrenaline as well as the responsiveness in disease states to therapeutic agents acting via alpha-adrenoceptors.

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Section: Discussionsupporting

confidence: 46%