Abstract:
:1. The present work describes the effects of inhibitors (amiloride and ethylisopropylamiloride) and activators (quinoxaline and phenylephrine) of the Na(+)-H+ exchanger on the outflow of dopamine in rat kidney slices loaded with L-dihydroxyphenylalanine (L-DOPA). 2. Incubation of kidney slices loaded with 50 microM L-DOPA in the presence of increasing concentrations of amiloride or ethylisopropylamiloride (EIPA) resulted in a concentration-dependent decrease in the outflow of newly-formed dopamine; the IC50 value for EIPA was 5.6 +/- 0.3 microM. Phenylephrine and quinoxaline were found to produce a concentration-dependent increase in the outflow of newly-formed dopamine; the EC50 values for the phenylephrine and quinoxaline were, respectively, 0.9 +/- 0.1 and 0.08 +/- 0.01 microM. 3. The facilitatory effect of phenylephrine on the outflow of dopamine was found not to be affected by yohimbine (100 nM), but was abolished by prazosin (1 microM), whereas that of quinoxaline was found to be selectively antagonized by yohimbine (100 nM), but not by prazosin (1 microM); EIPA (10 microM) was also found to abolish the effect of both phenylephrine and quinoxaline. The facilitatory effect of quinoxaline was also found to be reduced by 42-48% and 56-78% by, dibutyryl adenosine cyclic 3',5'-monophosphate (dibutyryl cyclic AMP; 250 microM) and forskolin (10 microM), respectively, but not by the protein kinase C (PKC) inhibitor, (+)-sphingosine (10 microM). In contrast, (+)-sphingosine (10 microM) was found to antagonize markedly (43- 69% reduction) the facilitatory effect of phenylephrine; dibutyrylcyclic AMP (250 microM) and forskolin (10 microM) were also found to reduce significantly the facilitatory effect of phenylephrine, by 42-53% and 44-59% respectively.4. A synergistic effect between alphal- and alpha2-adrenoceptors was observed for submaximal concentrations of quinoxaline (50 nM) and phenylephrine or submaximal concentrations of phenylephrine (0.5 microM) and quinoxaline, but not for maximal effective concentrations of either agonist. Dibutyryl cyclic AMP(250 microM) or forskolin (10 microM) produced a marked decrease (35-85% reduction) of the synergistic effect between phenylephrine and quinoxaline. The addition of phorbol 12,13-dibutyrate (PDBu; 500 nM) was found not to alter the outflow of newly-formed dopamine, but did potentiate (18-42% increase) the facilitatory effect of quinoxaline on the amine outflow. This effect was found to occur for submaximal concentrations of quinoxaline (10, 50 and 100 nM) and found to be antagonized by (+)-sphingosine(10 microM). In contrast, PDBu (500 nM) was found not to potentiate the facilitatory effect of phenylephrine on dopamine outflow.5. In conclusion, inhibition of the Na+-H+ antiport by amiloride and EIPA results in considerable reduction in the outflow of newly-formed dopamine, whereas the activation of this mechanism by both phenylephrine and quinoxaline results in facilitation of the outflow of dopamine; this effect is selectively reversed by alphal- and alpha2-adrenoceptor antagonists and EIPA. The synergistic effect between quinoxaline and phenylephrine may be related to an amplification of a reaction at a given point in the post-receptor transducing pathway.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Soares-da-Silva Pdoi
10.1111/j.1476-5381.1993.tb13608.xsubject
Has Abstractpub_date
1993-06-01 00:00:00pages
569-76issue
2eissn
0007-1188issn
1476-5381journal_volume
109pub_type
杂志文章abstract::1. Female mice of the Hough/Porton and Tuck/TO strains were found to be more sensitive than male mice to the diuretic effects of oral and intravenous doses of ethacrynic acid. 2. The sensitivity of Hough/Porton male mice to ethacrynic acid was increased after pretreatment with stilboestrol and the sensitivity of femal...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1977.tb07536.x
更新日期:1977-08-01 00:00:00
abstract::In recent years, late-stage clinical drug development that primarily focuses on urogenital targets has centered around four areas of medical need (both unmet need and aiming to improve on existing therapies). These include male sexual dysfunction (MSD), female sexual dysfunction (FSD), prostatic pathology (neoplastic,...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
doi:10.1038/sj.bjp.0706638
更新日期:2006-02-01 00:00:00
abstract::1. The contribution of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) to non-adrenergic non-cholinergic (NANC) relaxations in the pig gastric fundus was investigated. 2. Circular and longitudinal muscle strips were mounted for isotonic registration in the presence of atropine and guanethidine; tone was ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1995.tb16406.x
更新日期:1995-10-01 00:00:00
abstract::The effects of several anticonvulsant drugs on sodium-dependent high affinity choline uptake (HACU) in mouse hippocampal synaptosomes was investigated. HACU was measured in vitro after in vivo administration of the drug to mice. HACU was inhibited by drugs which have in common the ability to facilitate gamma-aminobuty...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:
更新日期:1985-01-01 00:00:00
abstract::Recent clinical studies have demonstrated that angiotensin II type 1 (AT(1) ) receptor blockers (ARBs) reduce the onset of stroke, stroke severity and the incidence and progression of Alzheimer's disease and dementia. We can expect that ARBs exert these effects by both AT(1) receptor blockade and angiotensin II type 2...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
doi:10.1111/j.1476-5381.2010.01167.x
更新日期:2011-07-01 00:00:00
abstract::1. In the present study we tested the hypothesis that insulin-like growth factor-1 (IGF-1) modulates resting chloride conductance (G(Cl)) of rat skeletal muscle by activating a phosphatase and that the chloride channel, based on the activity of phosphorylating-dephosphorylating pathways, has different sensitivity to s...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0702107
更新日期:1998-10-01 00:00:00
abstract::1. The effects of bretylium have been investigated on the content and sub-cellular distribution of noradrenaline in cat spleen and on the overflow of noradrenaline in response to stimulation of the splenic nerve.2. Bretylium, 15 min after its administration, produces a significant depletion of noradrenaline in only th...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1970.tb09887.x
更新日期:1970-04-01 00:00:00
abstract::1. The effect of 4-aminopyridine (4-AP) on the slow afterhyperpolarization (sAHP) seen after high frequency dendritic or somatic firing was investigated in rat hippocampal CA1 pyramidal neurones (PC). Intracellular recordings were obtained from the distal apical dendrites and somata and suprathreshold depolarizing cur...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704533
更新日期:2002-02-01 00:00:00
abstract::1 New 2H-1,4-benzoxazine derivatives were synthesized and tested for their agonist properties on the ATP-sensitive K(+) channels (K(ATP)) of native rat skeletal muscle fibres by using the patch-clamp technique. The novel modifications involved the introduction at position 2 of the benzoxazine ring of alkyl substituent...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705233
更新日期:2003-05-01 00:00:00
abstract::Cyclic adenosine monophosphate (cAMP) is one of the second messengers critically involved in the molecular mechanisms underlying memory formation. In the CNS, the availability of cAMP is tightly controlled by phosphodiesterase 4 (PDE4), a family of enzymes that degrades the cyclic nucleotide to inactive AMP. Among the...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
doi:10.1111/bph.13257
更新日期:2015-10-01 00:00:00
abstract::Adrenomedullin (AM) has two known receptors formed by the calcitonin receptor-like receptor (CL) and receptor activity-modifying protein (RAMP) 2 or 3: we report the effects of the antagonist fragments of human AM and CGRP (AM22-52 and CGRP8-37) in inhibiting AM at human (h), rat (r) and mixed species CL/RAMP2 and CL/...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705472
更新日期:2003-10-01 00:00:00
abstract::1. The 5-hydroxytryptamine (5-HT)-receptor subtype and affinity for 5-HT was determined in large and small coronary arteries isolated as ring segments from the proximal and distal part of the left coronary artery of 3 month (young) and 2-year old (old) rats. 2. Ketanserin induced a rightward shift of the 5-HT concentr...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1991.tb12167.x
更新日期:1991-01-01 00:00:00
abstract::The aim of this study was to characterize the angiotensin II receptors in isolated uterine arteries from non pregnant and pregnant rats, since it has been reported from binding studies that ovine uterine arteries contain AT2 receptors. Uterine arterial segments were obtained from virgin, non-pregnant and late pregnant...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0702210
更新日期:1998-12-01 00:00:00
abstract::1. The present study was designed to characterize the positive inotropic response to DPI 201-106 in isolated papillary muscle strips obtained from heart failure patients undergoing surgery. 2. The positive inotropic responses to isoprenaline and milrinone and cardiac beta-adrenoceptor density were also determined. 3. ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1989.tb16892.x
更新日期:1989-09-01 00:00:00
abstract::The effects of vasoactive substances on mean circulatory filling pressure (MCFP), an index of total body venous tone, were determined in conscious rats. Cumulative doses of saline (0.9% w/v NaCl solution), methoxamine (alpha 1-adrenoceptor agonist), B-HT920 (alpha 2-adrenoceptor agonist) noradrenaline and vasopressin,...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1986.tb10272.x
更新日期:1986-10-01 00:00:00
abstract::1. Short-circuit current (SCC) technique was used to study the adrenoceptors involved in the electrogenic chloride secretion by cultured cauda epididymal epithelium of rats. Stimulation of the epithelium with noradrenaline (primarily beta 1-adrenoceptor selective agonist), salbutamol (beta 2-adrenoceptor selective ago...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb14477.x
更新日期:1992-09-01 00:00:00
abstract::1. Impairment of nitric oxide (NO)/cyclic GMP production and/or increased activities of thromboxane A2 (TXA2) and endothelin-1 (ET-1) have been associated with pulmonary hypertension. We have analysed the interactions of noradrenaline (NA), the TXA2-mimetic U46619 and ET-1 with the relaxation induced via cyclic GMP in...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701257
更新日期:1997-08-01 00:00:00
abstract::By examination of compound action potentials in the saphenous nerve of the anaesthetized rat it has been shown that capsaicin causes a rapid, dose-dependent, failure of conduction in many C-fibres when applied directly to the nerve. A large reduction in C-fibre conduction occurs with concentrations as low as 110 micro...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1986.tb10256.x
更新日期:1986-10-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Peptides from venomous animals have long been important for understanding pain mechanisms and for the discovery of pain treatments. Here, we hypothesized that Phα1β, a peptide from the venom of the armed spider Phoneutria nigriventer, produces analgesia by blocking the TRPA1 channel. EXPERIMENTA...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.13652
更新日期:2017-01-01 00:00:00
abstract::1 The effects of presynaptic alpha-adrenoceptor blockade on both the efflux of 3H-transmitter and on the magnitude of the effector response were measured simultaneously in a smooth muscle preparation which responds to field stimulation with noradrenergic beta-receptor-mediated relaxation. 2 In the presence of atropine...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1983.tb09386.x
更新日期:1983-01-01 00:00:00
abstract::1. A quaternary derivative of (-)-hyoscyamine, phenthonium (Phen) induced a concentration-dependent increase in the rate of spontaneous quantal release of acetylcholine (ACh) at the mammalian neuromuscular junction, as shown by intracellular recordings of the miniature endplate potentials (m.e.p.ps) in rat diaphragm m...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1990.tb15825.x
更新日期:1990-07-01 00:00:00
abstract::Aminobisphosphonates (aminoBPs) are potent inhibitors of bone resorption. However, they cause undesirable inflammatory reactions, including fever, in humans. Intraperitoneal injection of aminoBPs into mice also induces inflammatory reactions, including a prolonged elevation of the activity of the histamine-forming enz...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0703460
更新日期:2000-08-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Small conductance calcium-activated potassium (KCa 2.x) channels have a widely accepted canonical function in regulating cellular excitability. In this study, we address a potential non-canonical function of KCa 2.x channels in breast cancer cell survival, using in vitro models. EXPERIMENTAL APP...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.13357
更新日期:2016-01-01 00:00:00
abstract::1 U46619, a prostaglandin H2 endoperoxide analogue and thromboxane A2 agonist, dose-dependently inhibited accumulation and metabolism of thromboxane B2 in the isolated perfused lung of the guinea-pig. At similar doses prostaglandins E1, E2, F1 alpha, F2 alpha, I2, 5, 6-trans-PGE2 and 8-iso-PGE1 were ineffective. 2 U46...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1983.tb09366.x
更新日期:1983-01-01 00:00:00
abstract:UNLABELLED:Sarcoplasmic reticular (SR) Ca(2+) -ATPase (SERCA2a) is central to cardiac electrophysiological and mechanical function. It ensures full diastolic relaxation minimizing delayed after-potentials that would otherwise compromise membrane electrophysiological stability, and optimizes SR Ca(2+) refilling and syst...
journal_title:British journal of pharmacology
pub_type: 评论,杂志文章
doi:10.1111/bph.12288
更新日期:2013-10-01 00:00:00
abstract::1. Dopamine efflux following single pulse or train of pulse stimulations was measured in slices of rat caudate putamen, nucleus accumbens and tuberculum olfactorium, using fast cyclic voltammetry at a carbon fibre microelectrode; 1, 5, 10, 20 or 50 pulses were applied at each location at frequencies varying from 10 Hz...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb14355.x
更新日期:1992-06-01 00:00:00
abstract::1. The aim of the study was to investigate the mechanism of a novel effect of hypoxia on intracellular Ca(2+) signalling in rabbit cerebral arteriolar smooth muscle cells, an effect that was resistant to the L-type Ca(2+) channel antagonist methoxyverapamil (D600). 2.[Ca(2+)](i) of smooth muscle cells in intact arteri...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704547
更新日期:2002-02-01 00:00:00
abstract::Schizophrenia remains an elusive multifaceted disorder with all evidence of its onset and aetiology pointing to a complex interplay of genetic, nutritional, environmental and developmental factors. Although several molecular and structural abnormalities have been reported for schizophrenia, no diagnostic test or other...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
doi:10.1038/sj.bjp.0707658
更新日期:2008-03-01 00:00:00
abstract::1. The effects of 8-bromoguanosine 3':5'-cyclic monophosphate (8-bromo-cyclic GMP) on phenylephrine-induced contractions and phosphatidylinositol (PI) hydrolysis were investigated in rat isolated caudal artery. The effects of the nucleotide were compared to those of felodipine, a dihydropyridine Ca2+ channel antagonis...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1995.tb16394.x
更新日期:1995-09-01 00:00:00
abstract::1 alpha-Flupenthixol (alpha-FPT; 0.2 mg/kg i.p.) when administered to rats produced catalepsy. 2 Baclofen (10 mg/kg i.p.) given 30 min after alpha-FPT had a biphasic effect on the catalepsy. Initially there was a potentiation of the effect, followed by a significant attenuation of the degree of catalepsy. 3 Possible m...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1978.tb08460.x
更新日期:1978-02-01 00:00:00