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SEX DIFFERENCE IN BLOOD PRESSURE REGULATION IN AGING SPONTANEOUSLY HYPERTENSIVE RATS
Author(s) -
Mara Rodrigo Oscar,
Carmo Jussara Do,
Reckelhoff Jane F
Publication year - 2013
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.27.1_supplement.904.2
Subject(s) - medicine , blood pressure , endocrinology , heart rate , antagonism , antagonist , leptin , sympathetic nervous system , receptor , obesity
Leptin contributes to sympathetic activation via pro‐opiomelanocortin (POMC) neurons and thereby to increased blood pressure (BP). Whether melanacortin (MC3/4R) receptor contributes to hypertension (HT) in aging SHR is not clear. Our hypothesis was that MC3/4R activation contributes to HT in old SHR. Females and males (16–18 mos, n=6/grp) with MC3/4R antagonist SHU‐9119 (1 nmol/h icv for 7 days). MC3/4R antagonism increased the food intake by 56% in females and 71% in males (females: baseline: 17.1±2 g vs treatment: 26.6±1 g, p<0.001; males: baseline: 25±1.7 g, vs treatment: 43±2 g, p<0.001) and body weight by 18% in females and 23% in males (females: baseline: 217±11 g, vs treatment: 256±6 g, p<0.001; males: baseline: 356±27 g, vs treatment: 438±9 g, p<0.05). MC3/4R antagonism decreased BP (telemetry) and heart rate (HR) in males (BP: baseline: 172±5 vs treatment: 152±4 mmHg, p<0.05; HR: baseline: 321±4 vs treatment: 300±7 bpm, p<0.05), but had no effect in old females (MAP, baseline: 175±13 vs treatment: 172±10 mmHg, p=NS; HR: baseline: 345±9 vs Treatment: 332±9 bpm, p=NS). These results show that while MC3/4R activation contributes to the HT in old male SHR, sympathetic activation in old females is independent of the MC3/4R and suggests that sympathetic activation in aging women may have differential causes than in aging men. Supported by NIH PO1 HL51971, RO1 66072.