Drugs online research references
Kidney Int. 1989 Feb;35(2):647-53.
Adrenergic control of cAMP generation in rat inner medullary collecting tubule cells.
Teitelbaum I, Strasheim A, Berl T.
Department of Medicine, University of Colorado School of Medicine, Denver.
The adrenergic nervous system profoundly alters water excretion by both renal and extrarenal pathways. The effects of catecholamines on cultured rat inner medullary collecting tubule cells were studied. The beta-adrenergic agonist, isoproterenol, increases cAMP from 19.5 +/- 2.3 to 79.4 +/- 14.4 fm/micrograms protein, P less than 0.001. The response to arginine vasopressin (AVP) is also greater in the presence of isoproterenol, but the increment is unchanged when compared to that seen in the absence of AVP. The agonist effect of isoproterenol is blocked by propranolol but not by the specific beta 1 antagonist, atenolol. The effect of alpha-adrenergic stimulation was studied by the use of norepinephrine (NE) in the background of the beta blocker, propranolol. NE decreases AVP-stimulated cAMP generation from 190 +/- 11 to 117 +/- 10 fm/micrograms, P less than 0.001, N = 6. The specific alpha 2 antagonist, yohimbine, but not the alpha 1 antagonist, prazosin, prevents the NE-induced decrease as AVP-stimulated cAMP is restored to 187 +/- 19 fm/micrograms. Similarly the selective alpha 2 agonist, clonidine, significantly inhibits both AVP- and isoproterenol-mediated cAMP generation. To define the site of alpha 2 inhibition in the adenylate cyclase (AC) complex the effect of pertussis toxin (PT) was investigated. After pretreatment with PT (1-1000 ng/ml), AVP-stimulated cAMP was not inhibited by NE. The alpha 1 agonist, phenylephrine, fails to inhibit AC or to increase cytosolic Ca in these cells.(ABSTRACT TRUNCATED AT 250 WORDS)
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2565411&dopt=Abstract
J Pharmacol Exp Ther. 1991 Feb;256(2):767-72.
Selective distribution of alpha-1 and beta adrenoceptors in pregnant rat uterus visualized by autoradiography.
Legrand C, Vivat V, Rigolot C, Maltier JP.
Laboratoire de Physiologie de la Reproduction, CNRS URA 555, Universite Pierre et Marie Curie, Paris, France.
Receptor autoradiography using (-)-3-[125I]cyanopindolol and [3H]prazosin was used to study the distribution of beta and alpha-1 adrenoceptors in the rat uterus at early and midpregnancy. The binding of [3H]prazosin to slide-mounted sections at 25 degrees C was time dependent (K1 = 3.01 x 10(7) M-1 min-1, K2 = -0.0116 min-1) and saturable (1 nM). Competition binding curves with the selective alpha-1 and alpha-2 antagonists (prazosin, yohimbine) or alpha-1 and alpha-2 agonists (phenylephrine, clonidine) showed the presence of alpha-1 adrenoceptors; autoradiographic studies revealed that this subtype is highly localized in the circular layer of the myometrium during pregnancy. (-)-3-[125I]Cyanopindolol binding to slide-mounted sections of the pregnant uterus at 25 degrees C was time dependent (K1 = 4.68 x 10(8) M-1 min-1, K2 = -0.0117 min-1) and saturable (200 pM). Competition binding curves with beta-1 or beta-2 selective agonists (dobutamine, metaproterenol) and antagonists (atenolol, ICI 118,551) revealed the presence of beta adrenoceptors in the proportion of 67% beta-2 to 33% beta-1. Hyperfilm exposed to sections of the whole pregnant uterus incubated with (-)-3-[125I]cyanopindolol with or without ICI 118,551 or atenolol showed a high density of beta-2 adrenoceptors in the longitudinal layer of the myometrium and in the placenta. A small density of beta-2 adrenoceptors was also located in the decidua basalis on day 8 of pregnancy.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1847211&dopt=Abstract
J Oral Pathol. 1986 Feb;15(2):66-70.
Growth of rat salivary glands after terbutaline or dobutamine.
Schneyer CA.
Six days after commencement of a regimen of twice daily administration of 25, 50, or 75 mg/kg body wt doses of the beta 1 adrenergic agonist, dobutamine, or the beta 2 adrenergic agonist, terbutaline, submandibular and parotid glands of rats were enlarged in size. The beta 1 receptor was responsible for mediation of these changes with both agonists, since the effects of either agonist were prevented when a 10 mg/kg dose of the beta 1 antagonist, atenolol, was injected 20 min prior to the agonists but were not prevented when the beta 2 antagonist butoxamine, was given prior to each agonist. The increase in gland size caused by dobutamine was more marked than that induced by terbutaline; total amount of DNA of the parotid gland was also higher with dobutamine than with terbutaline. The response of the parotid gland to each dose of either agonist was greater than that of the submandibular gland, suggesting that the parotid gland has more beta receptors than does submandibular gland. The data also show that the increase in cell size precedes an increase in cell number. The increase in cell size depends on activation of fewer receptors than are required for the increase in DNA, since at the same dose of dobutamine, e.g., increase in cell size but not cell number was observed; moreover, the same dosage effected an increase in DNA of parotid but not submandibular gland. The data thus show that enlargement of both glands, as well as increase in size and number of their acinar cells, is dependent on activation of beta 1 adrenoceptors only.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3083064&dopt=Abstract
online pharmacies ||
Hair Million herbal formula for hair loss and hair growth ||
Amoxicillin ||
Tramadol ||
Paxil ||
Rx Drugs USA, Prescription Drugs Online Pharmacy ||
Zithromax ||
online pharmacy ||
Antibiotics and prescription medications online literature ||
Antibiotics