@article{1462c805df2c418e8da0971200988695,
title = "Differential transmural constrictor response to norepinephrine in rabbit carotid artery",
abstract = "1. 1. The constrictor response of isolated, perfused rabbit carotid artery to intra- (IN) and extra-(EX) luminal norepinephrine (NE, 5 × 10-3 to 10-1 mM) stimulation was studied. 2. 2. Maximal resistance to perfusion (R) was calculated and found to be equal for both IN and EX NE stimulation. 3. 3. However, ED50 for EX NE was increased compared to that for IN NE. 4. 4. In order to analyze the phasic components of the response to NE, the change in R during the first 30 sec of the NE response (initial ΔR) and the ΔR occurring during the remainder of the NE response (ΔR + 30) were determined and values for IN and EX NE were compared. 5. 5. The initial ΔR was greater for IN NE while ΔR + 30 was greater for EX NE. 6. 6. The IN NE response and the EX NE response were additive, but both completely blocked by phentolamine administered to either the luminal or adventitial side of the vessel. 7. 7. These data suggest that smooth muscle at the luminal and adventitial sides of rabbit carotid artery have different sensitivities to NE and respond to NE with different phasic characteristics.",
author = "Flaim, {Stephen F.} and Field, {John M.} and Robert Zelis",
note = "Funding Information: It has been shown that the vasoconstrictor response of smooth muscle to alpha adrenergic stimulation varies according to the position of the muscle cell within the tunica media of the vessel wall from rabbit thoracic aorta (Pascual et al., 1979), sheep carotid artery (Keatinge et al., 1976) and rabbit ear artery (McCalden et al., 1979). The purpose of the present study was to determine if this phenomenon occurred in the rabbit carotid artery as well as to attempt to further characterize the mechanism of this response. In order to achieve these goals, the response of intact isolated perfused segments of rabbit carotid artery was measured during norepinephrine stimulation applied to either the luminal or the adventitial surface or to both surfaces simultaneously under varying experimental conditions. The results of these studies indicate that muscle layers of the inner tunica media of rabbit carotid artery when stimulated to contract by norepinephrine administration can induce a greater increase in vascular resistance compared to adventitial muscle layers. Furthermore, inner tunica media muscle layers respond more rapidly to norepinephrine stimulation resulting in a faster rise in vascular resistance when compared to the response elicited from administration of norepinephrine to the adventitial muscle layers. When compared to adventi- * Presented in part at the Federation of American Societies for Experimental Biology meetings in Dallas. Texas, on April 7, 1979. t Supported in part. by: National Heart, Lung, and Blood Institute Public Health Service Grant Nos HL 17853, HL 05434, and HL 05601, the Sam Ostrow Cardiology Research Fund. and a grant from the American Heart Association York-Adams Chapter.",
year = "1981",
doi = "10.1016/0306-3623(81)90062-8",
language = "English (US)",
volume = "12",
pages = "295--301",
journal = "General Pharmacology",
issn = "0306-3623",
publisher = "Elsevier Inc.",
number = "4",
}