Effects of Urotensin I on the Isolated Rat Tail Artery

Pharmacology ◽  
1979 ◽  
Vol 18 (2) ◽  
pp. 72-79 ◽  
Author(s):  
M.E. Gerritsen ◽  
K. Lederis
Keyword(s):  
Rat Tail Artery ◽  
Tail Artery ◽  
Rat Tail ◽  
Isolated Rat

Three different vasoactive responses of rat tail artery to nicotine

1999 ◽  
Vol 78 (1) ◽  
pp. 20-28
Author(s):  
Rui Wang ◽  
Zunzhe Wang
Keyword(s):  
Smooth Muscles ◽  
Rat Tail Artery ◽  
Vascular Smooth Muscles ◽  
Vascular Effects ◽  
Tail Artery ◽  
Complete Relaxation ◽  
Underlying Mechanisms ◽  
Channel Currents ◽  
Rat Tail ◽  
Isolated Rat

The vasoactive effects of nicotine on isolated rat tail artery tissues were studied. Nicotine transiently contracted rat tail artery tissues (EC50, 55.6 ± 2 µM) in an extracellular Ca2+ dependent and endothelium-independent fashion. The blockade of alpha1-adrenoceptors, but not alpha2-adrenoceptors or P2X purinoceptors, inhibited the nicotine-induced contraction by 38 ± 7% (p < 0.05). Nicotine (1 mM) depolarized membrane by 13 ± 3 mV, but did not affect L-type Ca2+ channel currents, of the isolated rat tail artery smooth muscle cells. The phenylephrine-precontracted tail artery tissues were relaxed by nicotine (EC50, 0.90 ± 0.31 mM), which was significantly inhibited after the blockade of nicotinic receptors. Simultaneous removal of phenylephrine and nicotine, after a complete relaxation of the phenylephrine-precontracted tail artery strips was achieved by nicotine at accumulated concentrations (>=10 mM), triggered a Ca2+-dependent rebound long-lasting vasoconstriction (n = 20). This rebound contraction was abolished in the absence of calcium or in the presence of tetracaine in the bath solution. Pretreatment of vascular tissues with a nicotinic receptor antagonist did not affect the nicotine-induced vasoconstriction or nicotine withdrawal induced rebound contraction. The elucidation of the triphasic vascular effects of nicotine and the underlying mechanisms is important for a better understanding of the complex vascular actions of nicotine.Key words: nicotine, smokeless tobacco, vascular smooth muscles, contraction, relaxation.

Release of endogenous noradrenaline from the rat tail artery induced by veratridine

1982 ◽  
Vol 60 (6) ◽  
pp. 805-810 ◽  
Author(s):  
Vladimír Palatý
Keyword(s):  
Sodium Pump ◽  
Rat Tail Artery ◽  
Free Solution ◽  
Release Of Noradrenaline ◽  
Tail Artery ◽  
Low Concentrations ◽  
Endogenous Noradrenaline ◽  
Increased Activity ◽  
Rat Tail ◽  
Isolated Rat

The overflow of endogenous noradrenaline from the isolated rat tail artery was measured using a radioenzymatic method. Veratridine increased the overflow markedly even in the absence of external Ca2+. Modifications of the effect of 5 μM veratridine by tetrodotoxin, pargyline, cocaine, lidocaine, and phenoxybenzamine indicated that interaction of the alkaloid with the sodium channel induces primarily nonexocytotic release of noradrenaline. Ouabain inhibited the effect of 5 μM veratridine on the overflow into Ca2+ -free solution, but it greatly potentiated the effect if external Ca2+ was present. Potentiation of the effect of veratridine in Ca2+-free solution by cyanide was ouabain sensitive. These observations are consistent with the hypothesis that, at low concentrations of veratridine such as 5 μM, the initial cause of enhanced release of noradrenaline may be a consequence of increased activity of the sodium pump, namely increased consumption of ATP by the pump.

Inhibition of monoamine oxidase by amiloride

1985 ◽  
Vol 63 (12) ◽  
pp. 1586-1589 ◽  
Author(s):  
Vladimír Palatý
Keyword(s):  
Monoamine Oxidase ◽  
Brain Homogenate ◽  
Competitive Inhibitor ◽  
Rat Tail Artery ◽  
Monoamine Oxidase Activity ◽  
Tail Artery ◽  
Endogenous Noradrenaline ◽  
Rat Tail ◽  
Isolated Rat ◽  
External K

Amiloride was found to lower the overflow of 3,4-dihydroxyphenylethylene glycol from isolated rat tail artery. The overflow was reduced to about 50% in the presence of 10−5 M concentration of the drug. Reduced overflows of the glycol were observed also under conditions when the nonexocytotic release of endogenous noradrenaline was enhanced by tyramine, reserpine, or by the elevation of external K+ in the absence of extracellular Ca2+. They were accompanied by increased overflows of the amine. Amiloride inhibited monoamine oxidase activity (E.C. 1.4.3.4) of the A form in rat brain homogenate by acting as a competitive inhibitor.

Basal inhibitory action of endogenous endothelin on the sympathetic contraction in the isolated rat tail artery

1999 ◽  
Vol 384 (2-3) ◽  
pp. 163-167 ◽  
Author(s):  
Angel Luis Garcı́a-Villalón ◽  
Luis Monge ◽  
Nuria Fernández ◽  
Miguel Angel Sánchez ◽  
Marı́a Angeles Martı́nez ◽  
...  
Keyword(s):  
Inhibitory Action ◽  
Rat Tail Artery ◽  
Tail Artery ◽  
Rat Tail ◽  
Isolated Rat
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