adrenoceptors

adrenoceptors

transmembrane proteins on cells that are activated by noradrenaline released at sympathetic nerve endings or by circulating catecholamines. There are three main types: alpha-11), alpha-2 (α2) and beta (β) which mediate responses by different cellular mechanisms and are activated preferentially by different agonists. Each type has three subtypes. All subtypes respond strongly to noradrenaline, β most strongly to adrenaline, and certain synthetic dugs can distinguish between α1 and α2. Such differences account, for example, for smooth muscle relaxation in some tissues (β-mediated vasodilatation in skeletal muscle; bronchodilation in the lungs) and vasoconstriction in others (α-mediated, in gut and skin) during heightened sympathetic activity. International agreement is for 'adrenoceptor' but the use of 'adrenergic receptors' is still common in the USA.
References in periodicals archive ?
27] Estrogen increases the density and enhances the function of pre-synaptic alpha-2 adrenoceptors, resulting in a significant decrease of norepinephrine-induced responses; [28] and (vi) there may also be a role for nitric oxide (NO) which is produced in response to estrogen and is known to inhibit norepinephrine release presynaptically.
Clonidine stimulates alpha-2 adrenoceptors in the brain and spinal cord,[7,15,18] resulting in reduction of sympathetic outflow from the central nervous system and decreased in peripheral resistance, renal vascular resistance, plasma renin activity, heart rate, cardiac output and blood pressure.
2] Dexmedetomidine (1300:1) is more selective to the [alpha]-2 adrenoceptors than clonidine (39:1) and shows potent sedative analgesia-sparing properties.
Kettelhut, "Role of adrenoceptors and cAMP on the catecholamine-induced inhibition of proteolysis in rat skeletal muscle," The American Journal of Physiology--Endocrinology and Metabolism, vol.
As a2-adrenoceptor agonist Dexmedetomidine can impact on the LC-Norepinephrine through adreno- autoreceptors to regulate the body wakefulness; Dexmedetomidine can also regulate other awakening pathway activity by other adrenoceptors on other nerve terminals [17].
Localization and expression of alpha-1A, alpha-B and apha-D adrenoceptors in human ureter.
Adrenoceptors are important in uterine contractility but propranolol was unable to reduce spasmolytic effects of PGE by antagonizing the ([beta]-adrenoceptors.
In this study, dexmedetomidine premedication with the present study design resulted in slight hypotension and bradycardia, which could be attributed to postsynaptic activation of [alpha]2 adrenoceptors in the central nervous system (CNS) that inhibit sympathetic activity and thus can decrease blood pressure and heart rate (22).
Antinociceptive action of nitrous oxide is mediated by stimulation of noradrenergic neurons in the brainstem and activation of alpha-2B adrenoceptors.
30) These findings supported the premise that stimulation of beta-adrenoceptors with adrenoceptor agonists before an elective CS may promote postnatal respiratory and metabolic adaptation.
Their topics include the role of beta adrenoceptors in atypical anti-psychotic-mediated cognitive improvements, pediatric cardiology, the pharmaco-genomics of ophthalmic beta blockers, whether current doses used in clinical practice are effective in heart failure patients, and sexual dysfunction.