Involvement of Ca2+ mobilization in the amplifying effect of serotonin on responses of rabbit isolated ear artery to exogenous noradrenaline.
Naunyn Schmiedebergs Arch Pharmacol
; 337(5): 500-3, 1988 May.
Article
em En
| MEDLINE
| ID: mdl-3412490
The present study examined the involvement of Ca2+ mobilization in the amplifying effect of serotonin on steady-state responses of rabbit isolated perfused ear artery to exogenous noradrenaline (NA; 0.001-3 mumol/l). In contrast to its marked amplifying effect on responses to NA, serotonin in the subconstrictor concentration of 100 nmol/l had no effect on responses to KCl. The Ca2+-entry blocking drug diltiazem (10 mumol/l) decreased responses to NA; in addition, the amplifying effect of serotonin on responses to NA was reduced by diltiazem. Lowering the concentration of Ca2+ in the Krebs-Henseleit perfusion solution from 2.5 to 0.25 mmol/l also reduced both responses to NA and the amplifying effect of serotonin. Using the method of Manzini et al. (1982), separate intra- and extracellular Ca2+-dependent responses to NA were obtained. Serotonin had no effect on intracellular Ca2+-dependent responses to NA but enhanced extracellular Ca2+-dependent NA responses. These results suggest that the amplifying effect of serotonin on responses of rabbit ear artery to exogenous NA involves a selective enhancement of the component of the NA response which is dependent on extracellular Ca2+; serotonin may increase NA-evoked entry of Ca2+ into the vascular smooth muscle cells through receptor-operated Ca2+ channels.
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Base de dados:
MEDLINE
Assunto principal:
Serotonina
/
Norepinefrina
/
Cálcio
/
Músculo Liso Vascular
Limite:
Animals
Idioma:
En
Ano de publicação:
1988
Tipo de documento:
Article