Neuraminidase and Contractile Responses to Norepinephrine in Rat Tail Artery

1984 ◽  
Vol 21 (1) ◽  
pp. 1-11
Author(s):  
James H. Rice ◽  
Clinton Webb
Keyword(s):  
Rat Tail Artery ◽  
Contractile Responses ◽  
Tail Artery ◽  
Rat Tail

Effects of pertussis and cholera toxins on α-adrenoceptor function in rat tail artery: differences in hypertension

1993 ◽  
Vol 71 (10-11) ◽  
pp. 791-799 ◽  
Author(s):  
Xiao-Fang Li ◽  
Christopher R. Triggle
Keyword(s):  
Cholera Toxin ◽  
Pertussis Toxin ◽  
Rat Tail Artery ◽  
Response Curves ◽  
Contractile Responses ◽  
Tail Artery ◽  
Adrenoceptor Antagonist ◽  
Adrenoceptor Agonist ◽  
The Right ◽  
Rat Tail

The α1- and α2-adrenoceptor-stimulated contractile responses of rat tail artery rings were compared in Sprague–Dawley (SD), spontaneously hypertensive (SHR), and Wistar–Kyoto (WKY) rats that were untreated, treated with pertussis toxin, or treated with cholera toxin. The maximal responses, expressed as milligrams of tension, induced by clonidine (an α2-adrenoceptor agonist) and cirazoline (a selective (α1-adrenoceptor agonist) were significantly greater in SHR than in SD or WKY, and the tissues were more sensitive to the agonists in SHR or SD than in WKY. Yohimbine (0.1 μM), a selective α2-adrenoceptor antagonist, shifted the dose–response curves for clonidine to the right. The effects of yohimbine were greater in SD than in WKY or SHR, but not different between WKY and SHR. Prazosin (0.05 μM), a selective α1-adrenoceptor antagonist, shifted the dose–response curves of cirazoline to the right, but the effects of prazosin were not different among these three strains of rats. Nifedipine (0.05 μM) completely blocked the response to clonidine in SD and WKY; however, in SHR, approximately one-third of the response to clonidine was resistant to nifedipine. Nifedipine, at 0.05 μM, only partially inhibited responses to cirazoline in SD, SHR, and WKY, and no differences were noted between the strains. Pertussis toxin pretreatment (50 μg/kg, 3 days before experiment) almost completely blocked the responses to clonidine, but only partially inhibited those to cirazoline. After pertussis toxin pretreatment, the responses (maximal effects and EC50s) to clonidine and cirazoline were not significantly different in arteries from the three strains of rats. A combination of pertussis toxin and nifedipine resulted in an additive inhibition of the responses induced by cirazoline. cholera toxin pretreatment (0.3 mg/kg, 3 days before experiment), however, had no effects on the contractile responses induced by either clonidine or cirazoline, or on the inhibitory effects of nifedipine in SHR, SD, and WKY. These results indicate that (i) the maximal responses to α1- and α2-adrenoceptor agonists are enhanced in rat tail artery rings from SHR; (ii) tissues from SH and SD rats are also more sensitive to cirazoline and clonidine than are tissues from WKY; (iii) responses to clonidine, but not cirazoline, in tissues from the SHR are less sensitive to nifedipine than tissues from SD and WKY; (iv) a G-protein sensitive to pertussis but not cholera toxin is involved in the regulation of both α1 and α2-adrenoceptor signal transduction processes in rat tail artery smooth muscle; and (v) pretreatment with pertussis toxin reduces the enhanced response levels of SHR tissues so that the maximal contractile responses to both α1- and α2-adrenoceptor agonists are equivalent in arteries from the three strains of rats.Key words: pertussis toxin, cholera toxin, α1-adrenoceptor, α2-adrenoceptor, rat tail artery ring.

Ovariectomy eliminates sex differences in rat tail artery response to adrenergic nerve stimulation

1997 ◽  
Vol 272 (4) ◽  
pp. H1819-H1825 ◽  
Author(s):  
Z. Li ◽  
D. N. Krause ◽  
S. Doolen ◽  
S. P. Duckles
Keyword(s):  
Nerve Stimulation ◽  
Gonadal Hormones ◽  
Adrenergic Nerve ◽  
Rat Tail Artery ◽  
Vascular Response ◽  
Contractile Responses ◽  
Tail Artery ◽  
Resting Tension ◽  
Low Concentrations ◽  
Rat Tail

The influence of gonadal hormones on vasoconstrictor responses to adrenergic nerve stimulation was investigated by comparing tail arteries from intact and gonadectomized male and female Fisher 344 rats. Arterial ring segments from females were significantly less responsive to transmural nerve stimulation (1-8 Hz) than arteries from age-matched males. Significant male-female differences persisted after correcting the contractile responses for sex-related differences in arterial mass, optimal resting tension, and maximal contractile force. Arteries were taken from cycling, intact females in either proestrus, estrus, metestrus, or diestrus, but no significant differences were found among the four stages for vasoconstrictor responses to either adrenergic nerve stimulation or exogenous norepinephrine. These data suggest adrenergic function in the artery is not affected by hormonal variations during the estrous cycle. After bilateral ovariectomy, however, contractile responses of female arteries to adrenergic nerve stimulation were increased to levels similar to those observed in male arteries. Orchidectomy of males, in contrast, had no effect on neural-evoked contraction. Low concentrations of norepinephrine also produced greater contractile responses in male compared with female arteries; however, this sex-related difference was eliminated by orchidectomy but not ovariectomy. Taken together, the results indicate that circulating gonadal hormones contribute to gender differences observed in rat tail artery. Vasoconstrictor responses to exogenous norepinephrine appear to be enhanced by testicular hormones. In contrast, vasoconstriction induced by adrenergic nerve stimulation appears to be influenced by chronic exposure to circulating ovarian hormones, resulting in a smaller vascular response in female arteries.

Desensitization of the vascular contractile response to cumulative doses of α2-adrenoceptor agonists

1986 ◽  
Vol 64 (10) ◽  
pp. 1343-1345 ◽  
Author(s):  
D. W. Cheung
Keyword(s):  
Dose Response ◽  
Saphenous Vein ◽  
Contractile Response ◽  
Rat Tail Artery ◽  
Contractile Responses ◽  
Tail Artery ◽  
Α2 Adrenoceptor ◽  
Adrenoceptor Agonists ◽  
Rat Tail

Contractile responses to single or cumulative doses of α-adrenoceptor agonists were compared in the tail artery and the saphenous vein of the rat. In the rat tail artery, there were no differences in the dose–response relationships to noradrenaline, methoxamine, and KCl whether the agonists were applied as single or cumulative doses. However, the responses to single doses of clonidine and B-HT 920 were significantly larger than similar doses applied cumulatively. In the rat saphenous vein, responses to single doses of noradrenaline, clonidine, and B-HT 920 were also significantly larger than the corresponding cumulative doses. However, there was no difference in the responses to KCl. It was suggested that desensitization of α2-adrenoceptors in these vessels may result in the diminished responses to cumulative doses of the agonists. Desensitization appeared to be specific to α2-adrenoceptors, since the effect was not observed in responses mediated by the α1-adrenoceptors and KCl.

Fine tuning by protein kinases of CaV1.2 channel current in rat tail artery myocytes

2020 ◽  
Vol 182 ◽  
pp. 114263
Author(s):  
F. Fusi ◽  
P. Mugnai ◽  
A. Trezza ◽  
O. Spiga ◽  
G. Sgaragli
Keyword(s):  
Protein Kinases ◽  
Fine Tuning ◽  
Rat Tail Artery ◽  
Tail Artery ◽  
Channel Current ◽  
Cav1.2 Channel Current ◽  
Rat Tail

Neural control of reinnervated rat tail artery is restored despite incomplete perivascular plexus

2007 ◽  
Vol 135 (1-2) ◽  
pp. 130
Author(s):  
James A. Brock ◽  
Diana Tripovic ◽  
Svetlana Pianova ◽  
Elspeth M. McLachlan
Keyword(s):  
Neural Control ◽  
Rat Tail Artery ◽  
Tail Artery ◽  
Perivascular Plexus ◽  
Rat Tail
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