Participation of arterial baroreceptors input and peripheral vasopressin in the suppression of renal sympathetic nerve activity induced by central salt loading in conscious rats
K. Kato et al., Participation of arterial baroreceptors input and peripheral vasopressin in the suppression of renal sympathetic nerve activity induced by central salt loading in conscious rats, J AUTON NER, 76(2-3), 1999, pp. 83-92
We examined whether renal sympathetic nerve activity (RSNA) is suppressed i
n response to intracerebroventricular (i.c.v.) administration of hypertonic
saline (HS) in conscious rats. RSNA was suppressed by i.c.v. administratio
n of HS (0.3 M, 0.67 M, and 1.0 M, 1 mu 1/min for 20 min) in a concentratio
n-dependent manner, which was attenuated under pentobarbital anesthesia. To
elucidate mechanisms responsible for central MS-induced decrease in RSNA,
possible involvement of arterial baroreceptors and peripheral arginine vaso
pressin (AVP) secreted from the posterior pituitary gland was examined usin
g sinoaortic denervated (SAD) rats and non-peptide vasopressin receptor ant
agonists. The maximum suppression of RSNA (-81.5 +/- 5.5%) in control rats
was significantly attenuated to - 32.5 +/- 6.7% in SAD rats and to -55.8 +/
- 5.7% in rats pretreated with intravenous vasopressin V-1 receptor antagon
ist, OPC-21268 (5 mg/kg, i.v.). However, in SAD rats, pretreatment with vas
opressin V-1 receptor antagonist did not further affect the RSNA inhibition
induced by central salt loading. The results suggest that the suppression
of RSNA during central salt loading is mainly dependent on the arterial bar
oreceptors input and the 'additive' role of peripheral vasopressin. (C) 199
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