Drugs online research references
Am J Physiol. 1998 Sep;275(3 Pt 1):C702-10.
Alpha-adrenergic receptors regulate human lymphocyte amiloride-sensitive sodium channels.
Bubien JK, Cornwell T, Bradford AL, Fuller CM, DuVall MD, Benos DJ.
Department of Physiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
Two independent signal transduction pathways regulate lymphocyte amiloride-sensitive sodium channels (ASSCs), one utilizing cAMP as a second messenger and the other utilizing a GTP-binding protein. This implies that two plasma membrane receptors play a role in the regulation of lymphocyte ASSCs. In this study, we tested the hypothesis that alpha1- and alpha2-adrenergic receptors independently regulate lymphocyte ASSCs via the two previously identified second messengers. Direct measurements indicated that norepinephrine increased lymphocyte cAMP and activated ASSCs. The alpha2-specific inhibitor, yohimbine, blocked this activation, thereby linking alpha2-adrenergic receptors to ASSC regulation via cAMP. The alpha1-specific ligand, terazosin, acted as an agonist and activated lymphocyte ASSCs but inhibited ASSC current that had been preactivated by norepinephrine or 8-(4-chlorophenylthio) (CPT)-cAMP. Terazosin had no effect on the lymphocyte whole cell ASSC currents preactivated by treatment with pertussis toxin. This finding indirectly links alpha1-adrenergic receptors to lymphocyte ASSC regulation via GTP-binding proteins. Terazosin had no direct inhibitory or stimulatory effects on alpha,beta,gamma-endothelial sodium channels reconstituted into planar lipid bilayers and expressed in Xenopus oocytes, ruling out a direct interaction between terazosin and the channels. These findings support the hypothesis that both alpha1- and alpha2-adrenergic receptors independently regulate lymphocyte ASSCs via GTP-binding proteins and cAMP, respectively.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9730954&dopt=Abstract
Hosp Formul. 1991 Oct;26(10):811-3, 817-8.
Prescribing and usage patterns of two antihypertensive agents: a comparison of terazosin and enalapril.
Toiber F, Murthy VS.
Sinai Samaritan Medical Center, Milwaukee, WI 53201.
The prescribing and usage patterns of two antihypertensive agents, terazosin (Hytrin) and enalapril maleate (Vasotec) were analyzed and compared over a 6-month study period, using data from the PDS Alpha Data Base. The study analyzed several variables for both physician prescribing patterns and patient responses. Overall, the two agents performed equally well during the study period, with 6-month retention rates (% of patients who continued to take the same medication) of approximately 60%. Although both drugs are judged to be good candidates for first-line antihypertensive therapy, it was observed during the study that family practitioners write considerably more prescriptions for terazosin than enalapril, while internists write more enalapril prescriptions. We concluded that these differences in prescribing and usage patterns were largely attributable to the manufacturers' marketing strategies and to how various physicians perceive the two agents, rather than to actual clinical differences between them.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10136554&dopt=Abstract
Am J Physiol. 1998 Dec;275(6 Pt 2):R1867-74.
Central alpha2-receptor mechanisms contribute to enhanced renal responses during ketamine-xylazine anesthesia.
Cabral AD, Kapusta DR, Kenigs VA, Varner KJ.
Department of Physiological Sciences, Federal University of Espirito Santo, Brazil 29040-090.
We have recently developed an experimental approach to study central opioid control of renal function in anesthetized rats. This model system uses the intravenous infusion of the alpha2-agonist xylazine to enhance basal levels of urine flow rate and urinary sodium excretion in ketamine-anesthetized rats. This study examined the contribution of central and peripheral alpha2-adrenergic receptor mechanisms in mediating the enhanced renal excretory responses produced by xylazine. In ketamine-anesthetized rats, the enhanced levels of urine flow rate and urinary sodium excretion produced by the intravenous infusion of xylazine were reversed by the intravenous bolus injection of the alpha2-adrenoceptor antagonist yohimbine but not by the alpha1-adrenoceptor antagonist terazosin. In separate animals the intracerebroventricular administration of yohimbine only reduced urine flow rate by approximately 50% but did not alter urinary sodium excretion. The decrease in urine flow rate produced by intracerebroventricular yohimbine was reversed by the intravenous injection of a selective V2-vasopressin receptor antagonist. In a separate group of ketamine- and xylazine-anesthetized rats, the bilateral microinjection of yohimbine into the hypothalamic paraventricular nucleus (PVN) also significantly decreased urine flow rate by 54% without altering urinary sodium excretion. The microinjection of the beta-adrenoceptor antagonist propranolol into the PVN did not alter either renal excretory parameter. These results suggest that during intravenous infusion, xylazine increases urine flow rate by activating alpha2-adrenergic receptors in the PVN, which in turn decrease vasopressin release. The ability of alpha-adrenergic mechanisms in the PVN to selectively influence the renal handling of water, but not sodium, may contribute to the reported dissociation of the natriuretic and diuretic responses of alpha2-adrenoceptor agonists.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9843875&dopt=Abstract
Herbs and Pharmaceuticals Online ||
Hair Million herbal formula for hair loss and hair growth ||
Wellstreet online pharmacy for click-order prescription medications ||
Altace Online Pharmacy ||
Rx Drugs USA, Prescription Drugs Online Pharmacy ||
Insurance plans and information ||
Insurance policies for all purposes ||
Antibiotics and prescription medications online literature ||