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Intracerebroventricular (ICV) benzamil attenuates the maintenance phase of DOCA‐salt hypertension: Role of the paraventricular nucleus of the hypothalamus
Author(s) -
Abrams Joanna M,
Krawczewski Kimberly A,
Attar Aida,
Engeland William C,
Osborn John W
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1390-c
The present study was conducted to characterize the effect of ICV benzamil on the time course of DOCA‐salt hypertension and the role of the paraventricular nucleus (PVN) in these responses. Uninephrectomized rats were instrumented with a cannula connected to a minipump for infusion of benzamil (BENZ; N=6, 20 nmol/day) or vehicle (VEH; N=6), as well as a transmitter for continuous recording of arterial pressure (AP). DOCA (50 mg) was implanted subcutaneously and AP was recorded for 5 days while rats drank water. Baseline AP was similar (~100 mmHg) in both groups. Water was replaced with saline and AP recorded for 20 more days. During the first week of saline, group responses were indistinguishable. Starting on Day 7 of saline, marginal group differences in AP emerged. By Day 14, consistent differences emerged, with AP increasing to a greater extent in VEH (~130 mmHg) than BENZ (~115 mmHg; p<0.05). On Day 20, AP remained higher in VEH (~135 mmHg) as compared to BENZ (~120 mmHg; p <0.01). Brains were then harvested and processed for c‐Fos immunohistochemistry in the PVN as an indicator of neuronal activity. Initial results suggest that BENZ reduced PVN c‐Fos expression in DOCA‐salt rats. We conclude that BENZ treatment attenuates the maintenance phase of DOCA‐salt hypertension and that this may be a result of reduced neuronal activity in CNS pressure‐regulatory regions, including the PVN. HL 064178