OBJECTIVES The aim of this study was to investigate the role of peripheral presynaptic alpha-2 adrenergic receptors in modulating norepinephrine (NE) release in congestive heart failure (CHF). BACKGROUND Activation of the sympathetic nervous system is a hallmark of CHF. Clonidine, an imidazoline and adrenergic agonist with high selectivity for the alpha-2 adrenoceptor, has been shown to reduc...

b3-Adrenoceptor agonists have recently been introduced for the treatment of overactive urinary bladder syndrome. Their target, the b3-adrenoceptor, was discovered much later than b1and b2-adrenoceptors and exhibits unique properties which make extrapolation of findings from the other two subtypes difficult and the b3-adrenoceptor a less-understood subtype. This article discusses three aspects o...

Much of the acute cutaneous neurogenic inflammation after intradermal injection of capsaicin (CAP) in rats is mediated by dorsal root reflexes (DRRs), which cause the release of inflammatory agents from primary afferent terminals. Sympathetic efferents modulate neurogenic inflammation by interaction with primary afferent terminals. In this study, we examined if DRR-mediated flare after CAP inje...

We previously reported that nicotine-induced nitric oxide (NO)-mediated cerebral neurogenic vasodilation was dependent on intact sympathetic innervation. We hypothesized that nicotine acted on sympathetic nerve terminals to release norepinephrine (NE), which then acted on adrenoceptors located on the neighboring nitric oxidergic (NOergic) nerve terminals to release NO, resulting in vasodilation...

Vianen, Gerjanne J., Peter P. Obels, Guido E. E. J. M. van den Thillart, and Johan Zaagsma. -Adrenoceptors mediate inhibition of lipolysis in adipocytes of tilapia (Oreochromis mossambicus). Am J Physiol Endocrinol Metab 282: E318–E325, 2002; 10.1152/ajpendo.00187.2001.—The regulation of triglyceride mobilization by catecholamines was investigated in the teleost fish Oreochromis mossambicus (ti...

Human chorionic gonadotropin (hCG) is not only responsible for numerous pregnancy-related processes, but can affect the cardiovascular system as well. So far, however, information about any direct effect elicited by hCG on cardiac function, perfusion, and the mechanisms involved has remained scarce. Therefore, the present study aimed to determine the primary in vivo effect of hCG on cardiac con...

Beta-adrenoceptors are predominantly located in the cerebral cortex, nucleus accumbens and striatum. At lower densities, they are also present in amygdala, hippocampus and cerebellum. Beta-2 sites regulate glial proliferation during ontogenic development, after trauma and in neurodegenerative diseases. The densities of beta-1 adrenoceptors are changed by stress, in several mood disorders (depre...

Faucher FA, Gannier FE, Lignon JM, Cosnay P, Malécot CO. Roles of PKA, PI3K, and cPLA2 in the NO-mediated negative inotropic effect of 2-adrenoceptor agonists in guinea pig right papillary muscles. Am J Physiol Cell Physiol 294: C106–C117, 2008. First published October 17, 2007; doi:10.1152/ajpcell.00231.2007.— Although 2-adrenoceptors represent 15–25% of -adrenoceptors in the guinea pig heart,...

UK-14,304 [5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine]-mediated vasodilator responses were studied on wire myograph-mounted mouse aorta to determine the cells involved, mechanisms of action, and subtypes of alpha(2)-adrenoceptors. In the presence of induced tone, UK-14,304 produced concentration-related vasodilatation that was abolished by rauwolscine, N(omega)-nitro-L-arginine ...