ABSTRACT
Experiments were done on aortic rings (thoracic and abdominal) from young and retired breeder Lewis and Sprague-Dawley male rats. Constriction responses to norepinephrine, 5-hydroxytryptamine (5-HT), and prostaglandin F2 alpha, were done +/- the cyclooxygenase blockers, indomethacin or mefenamic acid. Indomethacin significantly depressed norepinephrine constriction in abdominal (but not thoracic) aorta of all groups. In additional studies of abdominal aorta from Lewis retired breeders, indomethacin and mefenamic acid depressed norepinephrine (but not 5-HT or prostaglandin F2 alpha) construction. Furthermore, indomethacin depressed norepinephrine constriction in vessels denuded of endothelial cells. The thromboxane receptor antagonist SQ 29548 did not alter norepinephrine constriction. Thus, in rat abdominal aorta, norepinephrine constriction is mediated by a constrictor prostanoid of vascular smooth muscle origin that is not thromboxane A2.
Subject(s)
Aorta, Abdominal/drug effects , Aorta, Thoracic/drug effects , Cyclooxygenase Inhibitors/pharmacology , Muscle, Smooth, Vascular/drug effects , Norepinephrine/antagonists & inhibitors , Adrenergic alpha-Antagonists/pharmacology , Adrenergic beta-Antagonists/pharmacology , Aging/physiology , Animals , Bridged Bicyclo Compounds, Heterocyclic , Dinoprost/pharmacology , Endothelium, Vascular/drug effects , Endothelium, Vascular/physiology , Fatty Acids, Unsaturated , Hydrazines/pharmacology , In Vitro Techniques , Indomethacin/pharmacology , Male , Mefenamic Acid/pharmacology , Norepinephrine/pharmacology , Rats , Rats, Inbred Lew , Rats, Sprague-Dawley , Receptors, Thromboxane/antagonists & inhibitors , Serotonin/pharmacology , Species SpecificityABSTRACT
To assess the effects of markedly restricted food intake versus ad libitum feeding or a slightly restricted feeding regimen during the period of organogenesis we fed groups of 16-18 pregnant rabbits Purina Certified High Fiber Chow ad libitum, 150 g/day, 75 g/day, or 15 g/day on Gestation Days 6 to 18 inclusive. Prior to and after organogenesis the animals were provided food ad libitum (ad lib). Clinical observations, body weights, and food and water consumption were recorded daily. On Gestation Day 30 each doe was euthanatized and necropsied, and maternal and fetal data were collected. Each fetus was examined for external, visceral, and skeletal variations and malformations. Ossification parameters were also evaluated. Statistical analyses were conducted in two ways, first comparing the restricted groups to the ad lib group and second comparing the 15 and 75 g/day groups to the 150 g/day group. During Days 6-18, the 15 and 75 g/day groups had significantly decreased weight gain (actual weight loss), compared to the groups fed 150 g/day or ad lib. Water consumption was also significantly decreased in the 15 g/day group during this period, compared to the ad lib group. When food was provided ad lib on Days 19-30 to the restricted groups, weight gain was significantly higher in the 15 and 75 g/day groups than the group previously given 150 g/day and the ad lib group. There were no differences in water consumption during that period. Abortion occurred in three 15 g/day animals.(ABSTRACT TRUNCATED AT 250 WORDS)
