Responses of coronary arteries to neurotransmitters: changes with sexual maturity in the female rabbit.
Vasomotor responses of isolated coronary arteries to peptide and nonpeptide neurotransmitter agents changed with the development of sexual maturity in female New Zealand white rabbits aged 4-12 months. There was a significant reduction from 4- to 12-month-old animals in both the direct smooth muscle vasodilator responses to calcitonin gene-related peptide (p less than 0.01) and vasoactive intestinal polypeptide (p less than 0.001), and in the endothelium-mediated response to substance P (p less than 0.005). Vasodilator responses to concentrations of acetylcholine (ACh) greater than 0.1 microM were virtually absent in the 6- and 12-month-old animals. No change in maximal relaxation to noradrenaline was seen with maturation, although there was a small significant increase in potency. The contractile response of the smooth muscle to 30 mM KCl declined steadily as the animals matured, but the maximal contraction to ACh (p less than 0.05), neuropeptide Y (p less than 0.02), and serotonin (p less than 0.05) increased significantly between 4 and 12 months of age. These results indicate that following sexual maturation in the female rabbit, the epicardial coronary artery shows a significant increase in maximum responses to vasoconstrictor neurotransmitter agents and, at the same time, a marked decline in responses to some vasodilator agents, both those acting directly on the smooth muscle and those acting via the endothelium.
Corr
L A
LA
National Heart and Lung Institute, University College, London.
Poole-Wilson
P
P
Burnstock
G
G
D000109:Acetylcholine / Q000378:metabolism / Q000494:pharmacology; D000375:Aging / Q000502:physiology; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D003331:Coronary Vessels / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology; D012741:Sexual Maturation; D013373:Substance P / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
D009478:Neuropeptide Y; D018377:Neurotransmitter Agents; D012701:Serotonin; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D011189:Potassium Chloride; D015740:Calcitonin Gene-Related Peptide; D000109:Acetylcholine; D009638:Norepinephrine