The role of adrenergic agents in augmenting proximal tubular salt and water flux, was studied in a preparation of freshly isolated rabbit renal proximal tubular cells in suspension. Norepinephrine (NE, 10(-5) M) increased sodium influx (JNa) 60 +/- 5% above control value. The alpha adrenergic antagonist, phentolamine (10(-5) M), inhibited the NE-induced enhanced JNa by 90 +/- 2%, while the beta...

alpha-Adrenergic stimulation is known to enhance myocardial contractility. Adult rat left ventricular myocytes bathed in 1 mM [Ca2+] (Ca0) and electrically stimulated at 0.2 Hz responded to alpha-adrenergic stimulation with 50 microM phenylephrine and 1 microM propranolol with an increase in twitch amplitude to 177.1 +/- 25.6% of control (mean +/- SEM). In contrast, when cell Ca2+ loading was i...

Because of the central role of adrenergic mechanisms in the expression of crucial genes during brown adipocyte differentiation, we examined the activation (phosphorylation) of CREB (cAMP-response-element-binding protein) in mouse brown adipocytes in primary culture. We found that noradrenaline ('norepinephrine') stimulated CREB phosphorylation rapidly (maximum effect in < or =5 min with slow de...

The goal of this study was to test the hypothesis that circulating catecholamines are primarily responsible for alpha-adrenergic coronary vasoconstriction during submaximal exercise. The experimental series consisted of chronic studies in which a regional left ventricular sympathectomy was performed with phenol. Myocardial perfusion to the innervated and sympathectomized left ventricular region...

We examined whether insulin and catecholamines share common pathways for their stimulating effects on glucose uptake. We perfused isolated working rat hearts with Krebs-Henseleit buffer containing [2-3H]glucose (5 mmol/L, 0.05 microCi/mL) and sodium oleate (0.4 mmol/L). In the absence or presence of the phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin (3 micromol/L), we added insulin ...

Tocolytic therapy with beta-adrenergic receptor agonists is a standard regimen to prevent preterm birth. Agonists exposure of beta-adrenergic receptors causes receptor desensitization in other organs, and this may limit the therapeutic value of beta-adrenergic receptor agonists. To study the effects of prolonged beta-adrenergic agonist treatment in human myometrium, we obtained biopsies during ...

The acute in vitro and in vivo effects of long-chain fatty acids (LCFAs) on the regulation of adrenergic lipolysis were investigated in human adipose tissue. The effect of a 2 h incubation, without or with LCFA (200 mumol/l), on basal and hormonally induced lipolysis was tested in vitro on isolated fat cells. The lipolytic response to epinephrine was enhanced by suppression of the antilipolytic...

Introduction: There are many similarities between memory impairment in patients suffering from Alzheimer and animals treated by Cannabinoids. The agonists of Cannabinoid receptors affect on a variety of memories and leanings. The present study aims to investigate the role of &alpha;-1-adrenergic receptors in central region of amygdala in state-dependent learning induced by WIN55,212-2 (cannabin...

The nonselective alpha-adrenergic antagonist, phenoxybenzamine, has been used in the treatment of neuropathic pain syndromes, specifically, complex regional pain syndrome (CRPS) types I and II. This agent has also previously been used in intravenous regional peripheral blocks for treatment of CRPS I; however, an intravenous preparation of phenoxybenzamine is not currently available in the U.S.A...