摘要:

The action of drugs on circular smooth muscle from rabbit renal artery, renal vein, mesenteric vein, inferior vena cava, guinea pig bronchus, and mouse trachea was studied using an inexpensive modification of the method of Bevan, Nielsen and Ovvman, and Bevan and Osher. Two 30-gauge disposable stainless steel hypodermic needles supported the tissue rings in a standard 10-ml isolated muscle bath. All the blood vessels contracted to norepinephrine, histamine, and KCl. The veins, unlike the renal artery, did not respond maximally to KCl and did not contract at all to serotonin. The guinea pig bronchi contracted to carbachol, histamine, and KCl and relaxed to isoproterenol. The mouse trachea contracted maximally to carbachol, did not contract to histamine, and contracted to 50% of maximum in response to KCl. Thus, standard isolated tissue baths can be inexpensively adapted for the study of relatively small blood vessels and airways (about 1 mm in diameter).

ISSN:1018-1172    

DOI:10.1159/000158110

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

A survey has been made of mechanisms associated with vascular adrenergic neuroeffector transmission in the lamb fetuses between 53 days and term gestation. The common carotid artery was isolated for studies of enzymic activities, uptake of norepinephrine (NE) and reactivity to vasoactive agents. The extra-neuronal NE uptake, monoamine oxidase and catechol-O-methyltransferase activities were present in the carotid artery of the youngest fetuses. The contractile responses to NE and serotonin and neuronal NE uptake preceded the response to adrenergic nerve stimulation during fetal growth. These results suggest that the mechanisms for adrenergic transmitter inactivation, transmitter action on vascular smooth muscle cells, and neuronal transmitter delivery develop in that sequence.

ISSN:1018-1172    

DOI:10.1159/000158111

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Particulate adenylate cyclase activity was examined in broken cell preparations of rat aorta and mesenteric artery from 3- to 5- and 9- to 13-week-old rats. While basal adenylate cyclase activity of the mesenteric artery was 4-fold greater than aortic enzyme activity, there was no difference in enzyme activity with age. GTP and the GTP analogue, 5’-guanylylimidodiρhosphate [Gpp(NH)p] stimulated adenylate cyclase activity. Stimulation by Gpp(NH)p did not differ with age for either tissue and occurred without a detectable lag. The vasodilators, isoproterenol, 2-chloroadenosine and prostaglandin E1, were ineffective in increasing adenylate cyclase activity, although marked stimulation was demonstrated with both sodium fluoride and Gpp(NH)p. Even in combination with Gpp(NH)p, isoproterenol did not increase particulate adenylate cyclase activity of these blood vessels; however, with intact arteries, isoproterenol (10–7 M) did increase aortic and mesenteric cyclic AMP levels. Isoproterenol increased cyclic AMP levels in rats of both ages, at a time when isoproterenol was less effective in maximally relaxing aortic strips from 9- to 13-week-old rats. These data indicate that diminished aortic relaxation with age is not associated with a reduced ability of vascular relaxants to increase aortic cyclic AMP levels. Furthermore, as a first step in establishing that guanine nucleotides are regulators of vascular adenylate cyclase, both GTP and Gpp(NH)p were found to be potent activators of adenylate cyclase from blood ves

ISSN:1018-1172    

DOI:10.1159/000158112

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Uptake and metabolism of tritiated noradrenaline by the mesenteric arteries of the dog and concomitant behaviour changes in endogenous noradrenaline are described. Posterior mesenteric artery strips were incubated for 30 min in Krebs solution containing (–)-7-3H-noradrenaline (1.084 µM); suitable pretreatments and/or preincubations were performed to study the influence of some drugs on these parameters. The arterial strips showed a high capacity to retain, accumulate and metabolize exogenous noradrenaline. At the concentration of noradrenaline studied, neuronal uptake and deamination represented the main inactivation mechanism, however, when neuronal uptake was blocked, extraneuronal deamination and o-methylation played a more important role. o-Methylation represented a vicarious enzymatic route when monoamine oxidase activity was inhibited. Iproniazid pretreatment increased markedly the endogenous noradrenaline content of the mesenteric arteries. During incubation with tritiated noradrenaline both an outflow of endogenous noradrenaline and an inflow of tritiated noradrenaline were observ

ISSN:1018-1172    

DOI:10.1159/000158113

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The effect of Sr++, Ba++ and Mn++ on calcium uptake by a plasma membrane-enriched fraction from mesenteric arteries of spontaneously hypertensive rats (SHR) was studied to determine what alterations in divalent cation interactions are associated with hypertension. 45Ca++ uptake in the presence of ATP by this fraction from SHR was significantly greater than that of normotensive rats (NWR). This 45Ca++ uptake by these fractions from both types of rat could be reduced by Ba++, Sr++ and nonradioactive Ca++, but not by Mn++; the ability of these cations to compete with 45 Ba++. In contrast, 45Ca++ uptake in the absence of ATP by this subcellular fraction from SHR was significantly less than that of NWR, and this passive 45Ca++ binding could be displaced by Mn++ in addition to the other cations. Both qualitative and quantitative differences were found between SHR and NWR in this study of the effects of cations on calcium uptake by arterial plasma membrane. These results suggest that 1 This investigation was supported by the Alberta Heart Foundation and the Medical Research Council of Canada. 2 In this paper, calcium uptake is used operationally to describe all processes (binding, transport, etc.) leading to calcium accumulation, and calcium transport refers only to the process whereby calcium is transported actively across the vesicle membrane. 3 Dr. Janis was a Fellow of the Canadian Heart Foundation, and his present address is Department of Physiology, Northwestern University Medical School, Chicago, IL 60611 (USA). the plasma membrane of SHR arteries has calcium-binding and -transport properties that are different from those of NWR. However, there is not a complete correlation between the reported effects of the cations on contraction of other arteries in hypertension and on calcium uptake by membranes of SHR and NWR.

ISSN:1018-1172    

DOI:10.1159/000158114

出版商:S. Karger AG    

年代:1977

数据来源: Karger