Effect of chronic vitamin E deficiency on sympathetic and sensorimotor function in rat mesenteric arteries.
1. Mesenteric arterial beds from male rats deprived of vitamin E for 12 months postweaning were isolated and perfused at 5 ml min-1. 2. The basal perfusion pressure of vitamin E-deficient preparations was significantly higher (34.0 +/- 1.9 mmHg, n = 15) than in age-matched controls (26.1 +/- 2 mmHg, n = 14; P < 0.01). 3. At basal tone, vasoconstrictor responses to electrical field stimulation (EFS) were not attenuated by vitamin E deficiency; at high stimulation frequencies, responses were enhanced. According to dose-response curves, exogenous noradrenaline was significantly more efficacious in preparations from vitamin E-deficient rats (P < 0.05). 4. In preparations with tone raised by methoxamine (6-20 microM) and in the presence of guanethidine (5 microM), EFS of perivascular sensorimotor nerves elicited frequency-dependent vasodilatation which was significantly attenuated by vitamin E deficiency. There was no difference in relaxation to calcitonin gene-related peptide (CGRP; 1.5 x 10(-11) mol), or to the sensory neurotoxin capsaicin (5 x 10(-11) mol). 5. Immunohistochemical analysis of CGRP-containing nerves in the superior mesenteric artery showed no differences in density of innervation. 6. In conclusion, chronic vitamin E deficiency impairs sensorimotor vasodilatation in rat mesenteric arteries; this does not appear to be due to changes in postjunctional receptors, or to a depletion of transmitter (CGRP) content of the superior mesenteric artery. Sensorimotor nerves appear to be more vulnerable than sympathetic nerves to chronic vitamin E deficiency.
Ralevic
V
V
Department of Anatomy and Developmental Biology, University College London, UK.
Hoyle
C H
CH
Goss-Sampson
M A
MA
Milla
P J
PJ
Burnstock
G
G
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007150:Immunohistochemistry; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013564:Sympathetic Nervous System / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects; D014810:Vitamin E / Q000494:pharmacology*
D014810:Vitamin E; D015740:Calcitonin Gene-Related Peptide; D009638:Norepinephrine