Sympathetic cotransmission in rabbit saphenous artery in vitro: effect of electric stimulation and potentiation by alpha,beta-methylene ATP.
Acta Pharmacol Sin
; 22(10): 907-12, 2001 Oct.
Article
en En
| MEDLINE
| ID: mdl-11749773
AIM: To analyze the cotransmission characteristics of contractile responses to electric field stimulation with submaximal voltage and short train in the rabbit saphenous artery. METHODS: Isometric vasoconstriction of the rabbit saphenous arterial rings was recorded, and the sympathetic nerves of the arterial rings were activated with electric field stimulation. RESULTS: Electric stimulation produced contractile responses in a frequency-dependent manner in the rabbit saphenous artery. Selective alpha1-adrenoceptor antagonist, prazosin (1 micromol/L) did not affect the vasoconstriction induced by electric stimulation at 2 Hz significantly, but inhibited 39.9 % - 53.8 % of the vasoconstriction at 8 - 16 Hz. On the other hand, desensitization of the P2X1 receptor with alpha,beta-methylene ATP (3 micromol/L) abolished all the vascular responses induced by stimulation at 2 Hz, and obviously potentiated those induced by stimulation at 16 Hz, but it did not affect the concentration-dependent response curves for exogenous norepinephrine. The vasoconstriction responses induced by electric stimulation were all abolished by the treatment of a combination of prazosin (1 micromol/L) and alpha,beta-methylene ATP (3 micromol/L). CONCLUSION: The sympathetic and purinergic contractile responses can be induced by 2 Hz stimulation, and ATP is the sole transmitter causing the vasoconstriction in the rabbit saphenous artery. Contractile responses to higher frequencies are related to both norepinephrine and ATP. Desensitization of the P2X1 receptor with alpha,beta-methylene ATP potentiates the vascular responses to electric stimulation via a presynaptic mechanism.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Adenosina Trifosfato
/
Antagonistas Adrenérgicos alfa
/
Fibras Adrenérgicas
/
Miembro Posterior
/
Metano
Límite:
Animals
Idioma:
En
Revista:
Acta Pharmacol Sin
Asunto de la revista:
FARMACOLOGIA
Año:
2001
Tipo del documento:
Article
País de afiliación:
China
Pais de publicación:
Estados Unidos