Individualities in post-serotonin attenuation and Na+/K+ pump activity in vascular smooth muscle.
Eur J Pharmacol
; 171(2-3): 189-99, 1989 Nov 21.
Article
em En
| MEDLINE
| ID: mdl-2620702
ABSTRACT
Prior treatment with serotonin (10(-8)-10(-7) M for 6 min) attenuated responses of rabbit mesenteric arteries to norepinephrine (NE) by 18-62%, but was without effect on the responses of the rabbit aorta. K+ relaxation responses in the mesenteric arteries were enhanced by serotonin, but in the aortic strips K+ relaxation occurred either before or after treatment with serotonin. Maximum relaxation to monensin was similar in the two tissues. Post-serotonin attenuation and K+ and monensin relaxation were blocked by ouabain, indicating that they depended on Na+/K+ pump stimulation. Intracellular Na+ contents (Nai) were determined in the vessels by the Li substitution method. Nai was greater, and was increased to a greater extent by serotonin and K(+)-free physiological salt solution in the mesenteric artery compared to the aorta, suggesting that the cell membrane of the mesenteric artery is leakier to Na+ than is that of the aorta. We conclude that the absence of post-serotonin attenuation in the aorta results from the failure of serotonin to increase Nai and thereby to stimulate the Na+/K+ pump in this tissue. This study demonstrates that important individualities in vascular smooth muscle reactivity even in the same animal may result from differences in membrane permeability to sodium.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Sódio
/
Serotonina
/
Músculo Liso Vascular
Limite:
Animals
Idioma:
En
Revista:
Eur J Pharmacol
Ano de publicação:
1989
Tipo de documento:
Article