摘要:

A number of factors which have been implicated in the response of the rabbit ear artery to adrenergic agents and stimuli are reviewed. Aspects discussed include: (a) the method of propagation of vasoconstriction in the arterial smooth muscle; (b) the interrelationship between the intramural distribution of sympathetic nerves and muscle, and the influence of uptake and enzymic inactivation on the response to norepinephrine, and (c) the influence of presynaptic adrenergic and cholinergic receptors on the response to sympathetic nerve stimulation.

ISSN:1018-1172    

DOI:10.1159/000158046

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The effect of sex hormones on subendothelial connective tissue in rabbit arteries was sought, and striking morphological alterations were noted after prolonged treatment. Depot preparations of testosterone cypionate, 100 mg/week, or estradiol cypionate, 200 µg/week, were injected intramuscularly into intact adult New Zealand male rabbits for 8–16 weeks. The iliac arteries were prepared for electron-microscopic examination from five rabbits in each treatment group and in four normal male rabbits. Thin sections were prepared from three randomly selected cross-sectional tissue blocks for each animal. A minimum of 7 µm of vessel circumference was studied in each block. Selection of an area for electron-microscopic examination was random, except that those sites in which the internal elastic lamina showed fragmentation were discarded. Electron micrographs at a single final magnification were evaluated ‘blind’ by several observers for qualitative difference in subendothelial constituents. In the control group, the subendothelium contained moderate numbers of elastin-associated microfibrils (MF); all the rabbits given testosterone consistently showed significantly fewer MF than the control. In contrast, rabbits given estradiol all had significantly greater numbers of MF. Statistical analysis of variance showed these difference to be significant at p

ISSN:1018-1172    

DOI:10.1159/000158047

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Adrenergic neuron blockade produced in rabbit aortic strips by bretylium and bethanidine has been studied. Differences were noted in the characteristics of approximately equal, strong neuron blockade produced by these two chemically different agents. The blockade produced by bretylium was readily reversed by washout of the drug from the tissue bath whereas blockade produced by bethanidine was slowly reversed. Desmethylimipramine accelerated the recovery after the washout of bretylium, but had little effect in accelerating recovery following the washout of bethanidine. Desmethylimipramine prevented the onset of blockade from bretylium whereas it only delayed the onset of blockade from bethanidine. Desmethylimipramine also completely antagonized an established blockade due to bretylium but only slightly antagonized an established blockade due to bethanidine. It is suggested that the differences observed between these two neuron blocking agents are the result of their differential retention inside the neuron: bretylium is not firmly bound, leaks out of the neuron and goes through a process of recycling across the cell membrane, while bethanidine is more firmly bound inside the neuron than bretylium, only slowly leaks out of the neuron and is not recycled back across the cell membrane.

ISSN:1018-1172    

DOI:10.1159/000158048

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Histamine has been found biochemically in the mammalian vascular wall. This study was undertaken in an effort to identify the presence of specific histamine-containing cells in walls of large blood vessels such as femoral artery and vein, brachial artery and vein, mesenteric artery and vein, renal artery and vein, and aorta. Segments of vessels from rats, cats, dogs, sheep, cows, humans and chickens were examined. Sections were prepared from fresh tissue by vibratome, from frozen tissue by cryostat and from freeze-dried and fixed tissues. Mast cells were visualized by staining with acidic toluidine blue and by reaction with orthophthalaldehyde to develop histamine fluorescence. Although mast cells were easily identified in preparations such as canine liver, ear and scrotal skin and rat tongue, no such cells were found in any species (except the cow) in any part of the vascular wall. The results indicate that in most species histamine is stored in the vascular wall in a non-mast cell pool which may well be in the smooth muscle cells themselves.

ISSN:1018-1172    

DOI:10.1159/000158049

出版商:S. Karger AG    

年代:1975

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158050

出版商:S. Karger AG    

年代:1975

数据来源: Karger