Abstract:
:1. Under normal experimental conditions, the rabbit isolated distal saphenous artery appears to contain a homogeneous population of postjunctional alpha 1-adrenoceptors. Prazosin competitively antagonized responses to noradrenaline (NA) with a pA2 value of 8.6, while a relatively high concentration of rauwolscine (1 microM), produced only a 2 fold rightward displacement of the NA cumulative concentration-response curve (CCRC). 2. Despite the fact that angiotensin II (AII) was without effect on responses to NA or phenylephrine in this preparation, this peptide made responses to NA less susceptible to the antagonistic action of prazosin. This was particularly evident on the lower portion of the CCRC for NA. These results suggest that in the presence of AII, NA produces contractile responses by an action mediated through a prazosin-resistant adrenoceptor. 3. An attempt was made to isolate a homogeneous population of postjunctional alpha 2-adrenoceptors by use of a receptor protection procedure involving the combination of rauwolscine and phenoxybenzamine. After the protection protocol no responses were observed to the alpha-adrenoceptor agonists NA, phenylephrine or UK-14304. In the presence of angiotensin II however, concentration-dependent contractions were observed to each of these agonists. Under these conditions the rank order of potency, UK-14304 greater than NA greater than phenylephrine, is consistent with that of an effect mediated through postjunctional alpha 2-adrenoceptors. 4. The responses to NA, after the protection protocol, in the presence of AII, were susceptible to the selective alpha 2-adrenoceptor antagonist, rauwolscine (1 microM), but resistant to the selective alpha 2-adrenoceptor antagonist prazosin (0.1 microM). Furthermore, the combination of rauwolscine (1 microM) and prazosin (0.1 I microM) was no more effective in blocking responses to NA than was rauwolscine (1 microM) alone. These results are consistent with the presence of a homogeneous population of postjunctional alpha 2-adrenoceptors. 5. Inducing a small degree of tone with a low concentration of the selective alpha 1-adrenoceptor agonist, phenylephrine, markedly increased the threshold sensitivity to the selective alpha 2-adrenoceptor agonist UK- 14304, in a manner analogous to that seen with All. 6. The results in the present study indicate that responses mediated via postjunctional alpha 2-adrenoceptors in the rabbit isolated distal saphenous artery are dependent upon a degree of vascular smooth muscle stimulation by some other receptor system. It is hypothesized that under normal experimental conditions, this function is fulfilled by stimulation of alpha l-adrenoceptors, while after alpha 1-adrenoceptor blockade the necessary positive influence can be provided by stimulation of All receptors. The implications for such an interaction between postjunctional alpha-adrenoceptor subtypes in demonstrating prazosin-resistant, rauwolscine- or yohimbine-sensitive responses in isolated blood vessels is discussed.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Dunn WR,McGrath JC,Wilson VGdoi
10.1111/j.1476-5381.1991.tb09815.xsubject
Has Abstractpub_date
1991-06-01 00:00:00pages
1484-92issue
2eissn
0007-1188issn
1476-5381journal_volume
103pub_type
杂志文章abstract::1. This study describes attempts to compare prostacyclin (IP-) receptors in human, pig, horse, rabbit and rat platelets and in circular muscle of human, rabbit and dog mesenteric and pig gastroepiploic arteries. Three stable prostacyclin analogues, iloprost, cicaprost and 6a-carba-prostacyclin (6a-carba-PGI2) and a pr...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1989.tb12001.x
更新日期:1989-07-01 00:00:00
abstract::1. We studied the effect of bradykinin on plasma exudation in the airways of the anaesthetized guinea-pig in vivo. Tissue content of extravasated Evans blue dye was used as an index of protein exudation in the larynx, trachea, main bronchi and intrapulmonary airways (i.p.a.). 2. Bradykinin increased the content of Eva...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1990.tb14150.x
更新日期:1990-11-01 00:00:00
abstract::1. The role of adrenal hormones in the regulation of the systemic and local production of tumour necrosis factor (TNF alpha) was examined in male Balb/c mice. 2. Intraperitoneal injection of 0.3 mg E. coli lipopolysaccharide (LPS, 0111:B4) led to high levels of circulating TNF alpha without stimulating TNF alpha produ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb15317.x
更新日期:1996-04-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Imiquimod is an immunomodulator approved for the treatment of basal cell carcinoma and has adverse side effects, including taste disturbances. Paracrine transmission, representing cell-cell communication within taste buds, has the potential to shape the final signals that taste buds transmit to t...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.13567
更新日期:2016-11-01 00:00:00
abstract::1. The electrophysiological effects of prazosin, a highly specific alpha 1-adrenoceptor antagonist, on transmembrane action potential characteristics were studied in guinea-pig papillary muscles. 2. At concentrations between 10(-6) M and 10(-5) M, prazosin produced a concentration-dependent decrease in the maximum ups...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1994.tb14796.x
更新日期:1994-03-01 00:00:00
abstract::1 A series of cationic, lipophilic histamine H1-receptor antagonists, neuroleptics, antidepressants and monoamine oxidase inhibitors were tested for their effects on anti-IgE-induced histamine release from human lung fragments in vitro. 2 They had a biphasic effect: at low concentrations a dose-related inhibition of h...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1980.tb07919.x
更新日期:1980-08-01 00:00:00
abstract::It is well documented that metabolic syndrome (i.e. a group of risk factors, such as abdominal obesity, elevated blood pressure, elevated fasting plasma glucose, high serum triglycerides and low cholesterol level in high-density lipoprotein), which raises the risk for heart disease and diabetes, is associated with inc...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
doi:10.1111/bph.12960
更新日期:2015-03-01 00:00:00
abstract::1. Two-electrode voltage clamp was used to study the effects of adenosine 3':5'-cyclic monophosphate (cyclic AMP) and guanosine 3':5'-cyclic monophosphate (cyclic GMP) on voltage-dependent ion channels in salivary gland cells of the leech, Haementeria ghilianii. 2. Intracellular cyclic AMP specifically blocked delayed...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1995.tb16673.x
更新日期:1995-09-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Subset of macrophages within the atheroma plaque displays a high glucose uptake activity. Nevertheless, the molecular mechanisms and the pathophysiological significance of this high glucose need remain unclear. While the role for hypoxia and hypoxia inducible factor 1α has been demonstrated, the ...
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pub_type: 杂志文章
doi:10.1111/bph.15358
更新日期:2020-12-29 00:00:00
abstract::1 Hypolipidaemic agents may increase biliary cholesterol in man, inducing a supersaturated bile. 2 To evaluate this possible side-effect, we have studied bile lipid secretion over a period of 8 h with intact enterohepatic circulation and 4 h with complete interruption in rats treated for two months with a salt of chol...
journal_title:British journal of pharmacology
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doi:10.1111/j.1476-5381.1981.tb10471.x
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abstract::The effect of the imidazolidine Sgd 101/75 (2-[2-methylindazol-4-imino]-imidazolidine HCl) on blood pressure, as well as its alpha-adrenoceptor agonist activity and affinity for these receptors, were examined in various animal preparations. After both intravenous administration to conscious spontaneously hypertensive ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1984.tb10072.x
更新日期:1984-02-01 00:00:00
abstract::1. The possible involvement of nitric oxide (NO) in the induction and expression of morphine tolerance and dependence was studied in mice. A two-day repeated injection regimen was used to induce morphine tolerance and dependence. Tolerance was assessed by the tail flick test and physical dependence by naloxone challen...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb15280.x
更新日期:1996-03-01 00:00:00
abstract::1 The effects of raising or lowering [Ca(2+)](o) or [Mg(2+)](o) on potential changes evoked by 5-hydroxytryptamine (5-HT) and by the nicotinic agonist, 1,1-dimethyl-4-phenyl piperazinium (DMPP) have been investigated.2 Changes in membrane potential were measured at the ganglion or in postganglionic axons by the sucros...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1981.tb16813.x
更新日期:1981-07-01 00:00:00
abstract::1. Endothelial cells from human umbilical veins were maintained in tissue culture. The fragility of lysosomal membranes were studied by microdensitometry. 2. Histamine (50 microM to 10 mM), 4-methylhistamine (100 nM to 10 mM) and dimaprit (100 nM to 10 mM) increased lysosomal fragility. 2-Thiazolylethylamine and 2-pyr...
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doi:10.1111/j.1476-5381.1981.tb09140.x
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0707284
更新日期:2007-07-01 00:00:00
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journal_title:British journal of pharmacology
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doi:10.1111/j.1476-5381.1993.tb13943.x
更新日期:1993-11-01 00:00:00
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更新日期:2017-09-01 00:00:00
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doi:10.1111/j.1476-5381.1996.tb15440.x
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更新日期:1972-04-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704127
更新日期:2001-07-01 00:00:00
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journal_title:British journal of pharmacology
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更新日期:2006-10-01 00:00:00
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更新日期:2000-11-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704903
更新日期:2002-11-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1991.tb12278.x
更新日期:1991-04-01 00:00:00
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更新日期:2015-07-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701086
更新日期:1997-05-01 00:00:00
abstract::Changes in the efficiency of the peristaltic reflex, acetylcholine (ACh) output and motor responses to transmural and periarterial nerve stimulation produced by bicuculline and gamma-aminobutyric acid (GABA) receptor desensitization were investigated in the guinea-pig isolated colon. Bicuculline, at concentrations una...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1987.tb16822.x
更新日期:1987-01-01 00:00:00
abstract::1. Hypercholesterolaemia often occurs in patients with type 2 diabetes, who therefore encounter administration of HMG-CoA reductase inhibitors. Alteration of pancreatic beta-cell function leading to an impaired insulin secretory response to glucose plays a crucial role in the pathogenesis of type 2 diabetes. Therefore...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0702397
更新日期:1999-03-01 00:00:00