Drugs online research references
Placenta. 1993 Nov-Dec;14(6):683-93.
Norepinephrine regulates human chorionic gonadotrophin production by first trimester trophoblast tissue in vitro.
Shi CZ, Zhuang LZ.
State Key Laboratory of Reproductive Biology, Chinese Academy of Sciences, Beijing.
The effect of norepinephrine (NE) upon human chorionic gonadotrophin (hCG) production by 6-8 week gestation placental explants has been investigated. NE (5 micrograms/ml) enhanced hCG secretion significantly from the second day of treatment. The stimulatory effect of NE on hCG secretion could be abolished by the alpha 1-receptor specific antagonist prazosin (10(-4) M) and partly diminished by the beta 1-receptor specific antagonist atenolol (10(-4) M), but was not influenced by the alpha 2-receptor specific antagonist yohimbine (10(-4) M). The involvement of the alpha-receptor in the regulation of hCG secretion was further confirmed by addition of the alpha-receptor agonist clonidine (10(-6) M) which had a similar stimulatory effect on hCG release but the effect was antagonized by both prazosin and yohimbine. Further study showed that NE induced a significant increase in cyclic adenosine monophosphate (cAMP) production by trophoblast tissue. Cyclic AMP secretion in the NE-treated group was fivefold higher than that of the control group. Both the protein kinase C (PKC) specific activator 1-deoyl-2-acetyl-sn-glycerol (OAG) and the PKC non-specific activator phorbol-12-myristate-13-acetate (PMA) had a stimulatory effect on hCG secretion, while the PKC inhibitor, 1-(5-isoquinolinylsulfonyl)-2-methyl-piperazine (H7) diminished the hCG secretion stimulated by NE. The effect of NE was blocked by the voltage-dependent calcium channel blocker nifedipine but not by the voltage-independent calcium channel blocker gadolinium chloride (GdCl3). On the other hand, anti-gonadotrophin releasing hormone (GnRH) IgG and the GnRH antagonist (D-Phe2, D-Trp6)-GnRH did not influence the stimulatory effect of NE on hCG release. The results indicate that NE regulates hCG production in human first trimester trophoblast tissue. The effect of NE was mainly mediated by alpha 1 and partly by beta 1 receptors. Cyclic AMP, the PKC signal transduction pathway and the voltage-dependent calcium channels were involved in NE action.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8153089&dopt=Abstract
Am J Physiol. 1994 Dec;267(6 Pt 2):R1445-8.
The nocturnal increase in human cerebrospinal fluid production is inhibited by a beta 1-receptor antagonist.
Nilsson C, Stahlberg F, Gideon P, Thomsen C, Henriksen O.
Department of Medical Cell Research, University of Lund, Sweden.
A circadian variation in human cerebrospinal fluid (CSF) production has recently been demonstrated using magnetic resonance phase imaging. A nightly peak in CSF production was found at approximately 0200, when production is approximately twice the daytime values. In the present study, we have investigated the effect of a beta 1-receptor antagonist, atenolol, on the production of CSF, specifically the nocturnal production peak. CSF production was measured in fourteen healthy volunteers of both sexes in the time interval 1500-1800, with or without drug administration (100 mg orally) at 1800, and a second measurement was made in the time interval 2300-0200. In the absence of drug administration, all nine volunteers showed a significant increase in CSF production at night, from 0.34 +/- 0.06 ml/min in the time interval 1500-1800 to 0.61 +/- 0.05 (SE) ml/min (P < 0.005), confirming the presence of a circadian variation in these individuals. One week later, the experiment was repeated in five of these volunteers, plus an additional five volunteers, but with the administration of 100 mg atenolol orally immediately after the first measurement (at 1800). In five of the volunteers a decrease in CSF production was seen at midnight compared with daytime production values; in two volunteers CSF production remained unchanged, while three volunteers showed increased production. The average CSF production was 32% lower at night (0.27 +/- 0.10 ml/min) compared with the afternoon (0.40 +/- 0.07 ml/min), after administration of atenolol (P = 0.37).(ABSTRACT TRUNCATED AT 250 WORDS)
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7810751&dopt=Abstract
Am J Physiol. 1994 Apr;266(4 Pt 2):R1148-53.
Cardiovascular effects of human recombinant interleukin-1 beta in conscious rats.
Bataillard A, Sassard J.
Department of Physiology and Clinical Pharmacology, Faculty of Pharmacy, Centre National de la Recherche Scientifique Unite de Recherche Associee 1483, Lyon, France.
Cardiovascular effects of human recombinant interleukin-1 beta (hrIL-1 beta) were investigated in normotensive rats using a computerized analysis of arterial blood pressure in conscious, unrestrained animals. Intravenous injection of hrIL-1 beta induced a rapid and short-lasting rise in blood pressure associated with a first slight tachycardia followed by a second sustained and pronounced increase in heart rate. These effects occurred in a dose-related manner. Pretreatment with a converting-enzyme inhibitor (perindopril) did not modify the hrIL-1 beta-induced increase in blood pressure. Blockade of beta 1-adrenoceptors (atenolol) prevented the tachycardia, but did not significantly affect the pressor response to hrIL-1 beta. On the contrary, the hrIL-1 beta-induced increase in blood pressure was inhibited by an alpha 1-adrenoceptor antagonist (prazosin), whereas the tachycardia was untouched. Finally, pretreatment with a cyclooxygenase inhibitor (indomethacin) completely abolished the cardiovascular response to hrIL-1 beta. These results suggest that the hrIL-1 beta-induced pressor response and associated tachycardia require the synthesis of prostaglandins and involve a sympathetic nervous system activation but do not depend on the renin-angiotensin system.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8184956&dopt=Abstract
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