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Chronic electrical stimulation of the ventral lateral periaqueductal grey (vlPAG) evokes a persistent and substantial hypotensive response in spontaneously hypertensive (SH) but not normotensive rats
Author(s) -
McBryde Fiona D,
Patel Nikunj,
Paton Julian FR
Publication year - 2011
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.25.1_supplement.646.12
Deep brain stimulation of the vlPAG is used for the clinical treatment of chronic neuropathic pain in man. It also produces sustained reductions in arterial pressure (AP) in hypertensive patients (Patel et al. Neurology , 2011; in press). We have developed an implantable electrical stimulation system and applied it to the vlPAG of conscious, freely moving rats. AP and heart rate (HR) responses were measured via telemetry to explore potential central mechanisms. When resting quietly rats were stimulated for 60 min at a series of frequencies (15, 20, 30, 40 Hz) with >30 min recovery between steps. SH rats (mean baseline AP 139±10mmHg; n=4) showed frequency‐dependent AP reductions (12±4 vs 28±6mmHg; 15 vs 40 Hz; p<0.05), which persisted throughout the stimulation period. In contrast, in Wistar rats (mean baseline AP 101±9mmHg; n=4) a smaller depressor response was evoked (1±2mmHg vs 4±2mmHg; 15 vs 40Hz), which tended to return to baseline after 20–30mins. In SH rats the depressor response was maintained throughout 3 days of continuous 10Hz vlPAG stimulation (135mmHg to 121mmHg; baseline vs day 3) and associated with a reduction in the low frequency power of systolic blood pressure (1.75 to 1.51 mmHg 2 ), suggesting sympathoinhibition. Thus, the vlPAG of the SH rat is a more effective depressor site than it is in Wistar rats. Our current studies are now determining the mechanisms for this. Royal Society and NIH funded research.