+ Most Popular
Cunninghamia lanceolata plantations in China
Mammalian lairs in paleo ecological studies and palynology
Studies on technological possibilities in utilization of anhydrous milk fat for production of recombined butter-like products
Should right-sided fibroelastomas be operated upon?
Large esophageal lipoma
Apoptosis in the mammalian thymus during normal histogenesis and under various in vitro and in vivo experimental conditions
Poissons characoides nouveaux ou non signales de l'Ilha do Bananal, Bresil
Desensitizing efficacy of Colgate Sensitive Maximum Strength and Fresh Mint Sensodyne dentifrices
Administration of fluid by subcutaneous infusion: revival of a forgotten method
Tundra mosquito control - an impossible dream?
Schizophrenia for primary care providers: how to contribute to the care of a vulnerable patient population
Geochemical pattern analysis; method of describing the Southeastern limestone regional aquifer system
Incidence of low birth weights in a hospital of Mexico City
Graded management intensity of grassland systems for enhancing floristic diversity
Microbiology and biochemistry of cheese and fermented milk
The ember tetra: a new pygmy characid tetra from the Rio das Mortes, Brazil, Hyphessobrycon amandae sp. n. (Pisces, Characoidei)
Risk factors of contrast-induced nephropathy in patients after coronary artery intervention
Renovation of onsite domestic wastewater in a poorly drained soil
Observations of the propagation velocity and formation mechanism of burst fractures caused by gunshot
Systolic blood pressure in a population of infants in the first year of life: the Brompton study
Haematological studies in rats fed with metanil yellow
Studies on pasteurellosis. I. A new species of Pasteurella encountered in chronic fowl cholera
Dormancy breaking and germination of Acacia salicina Lindl. seeds
therapy of lupus nephritis. a two-year prospective study

Alpha-receptor stimulation by endogenous and exogenous norepinephrine and blockade by phentolamine in pial arteries of cats

Alpha-receptor stimulation by endogenous and exogenous norepinephrine and blockade by phentolamine in pial arteries of cats

Circulation Research 37(2): 168-174

ISSN/ISBN: 0009-7330

PMID: 238756

DOI: 10.1161/01.res.37.2.168

The question regarding the existence of an alpha-adrenergic component of pial arterial tone was investigated using a microapplication technique combined with the measurement of vascular diameter. Concentration-response curves for the alpha-receptor blocker, phentolamine, revealed no vascular reaction for a concentration range from 2.5 x 10(-11) to 2.5 x 10(-7) M. At higher concentrations (up to 1.3 x 10(-3) M) concentration-dependent dilations were observed. Constrictions of pial arteries induced by perivascular injection of 2.5 x 10(-6) M norepinephrine could be reduced by 38% and 73% when phentolamine was applied simultaneously in concentrations of 2.5 x 10(-7) and 2.5 x 10(-6) M, respectively, whereas constrictions due to 2.5 x 10(-4) M norepinephrine were not reduced by 2.5 x 10(-6) M phentolamine, indicating a competitive antagonism between norepinephrine and phentolamine for pial arteries. Stimulation of the cervical sympathetic chain (90 seconds, 10 v, 1.4 msec, 20 Hz) induced constrictions of pial arteries (mean 12%) which could be reduced by two-thirds during the simultaneous application of 2.5 x 10(-7) M phentolamine. Since the constriction induced by norepinephrine applied exogenously or released endogenously could be reduced by a concentration of phentolamine which had no vascular effect per se, we conclude that the resting tone of the pial arteries is not influenced by an alpha-adrenergic component under our experimental conditions. The dilations induced by high concentrations of phentolamine are believed to be nonspecific.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 039219509

Download citation: RISBibTeXText

Related references

Responses of newborn pig pial arteries to sympathetic nervous stimulation and exogenous norepinephrine. Pediatric Research 19(11): 1210-1214, 1985

Alpha adrenoceptor stimulation with exogenous norepinephrine or release of endogenous norepinephrine, mimics ischemic preconditioning. Circulation 88(4 Part 2): I488, 1993

Interactions between perivascular norepinephrine and potassium or osmolarity on pial arteries of cats. Microvascular Research 14(2): 173-180, 1977

Alpha-adrenoceptor stimulation with exogenous norepinephrine or release of endogenous catecholamines mimics ischemic preconditioning. Circulation 90(2): 1023-1028, 1994

Norepinephrine infusion with and without alpha-adrenergic blockade by phentolamine increases salivary alpha amylase in healthy men. Psychoneuroendocrinology 49: 290-298, 2014

Determinants of response of pial arteries to norepinephrine and sympathetic nerve stimulation. Stroke 6(6): 654-658, 1975

Comparison of the blockade produced by dibenzyline, ilidar, tolazoline and phentolamine of the vasomotor responses in skin induced by sympathetic nerve stimulation with the blockade of its responses to L-epinephrine and L-norepinephrine. Journal of Pharmacology and Experimental Therapeutics 112(2): 218-230, 1954

Norepinephrine infusion without but not with alpha-adrenergic blockade by phentolamine increases coagulation parameter levels in healthy men. Psychoneuroendocrinology 71: 45-46, 2016

Smooth muscle alpha-2 adrenoceptors mediate vasoconstrictor responses to exogenous norepinephrine and to sympathetic stimulation to a greater extent in spontaneously hypertensive than in Wistar Kyoto rat tail arteries. Journal of Pharmacology and Experimental Therapeutics 231(1): 159-165, 1984

Comparison of blockade at alpha-adrenoceptors by thymoxamine and phentolamine in peripheral arteries and veins of man. British Journal of Pharmacology 44(2): 294-300, 1972

Vascular responses of ophthalmic arteries to exogenous and endogenous norepinephrine. Experimental Eye Research 48(4): 539-547, 1989

Interference of calcium entry blockade in vivo with pressor responses to alpha-adrenergic stimulation: effects of two unrelated blockers on responses to both exogenous and endogenously released norepinephrine. Circulation 69(6): 1171-1176, 1984

Effects of exogenous and endogenous norepinephrine on the oxygen availability of intact muscular arteries. Journal of Atherosclerosis Research 10(1): 11-18, 1969

Changes of peri vascular hydrogen ion activity on the smooth muscle of pial arteries of cats during electrical stimulation and application of drugs. Pfluegers Archiv European Journal of Physiology 343(Suppl.): 25, 1973

Efficiency of alpha receptor blockade by phentolamine in raymonds syndrome. Verhandlungen der Deutschen Gesellschaft fuer Innere Medizin 84: 1406-1408, 1978