Nicotine impairs reflex renal nerve and respiratory activity in deoxycorticosterone acetate-salt rats

S A Whitescarver, A M Roberts, R W Stremel, A E Jimenez, J C Passmore
1991 Hypertension  
Smoking exacerbates the increase in arterial pressure in hypertension. The effect of nicotine on the baroreceptor-mediated reflex responses of renal nerve activity (RNA), heart rate, and respiratory activity (minute diaphragmatic activity [MDA]) after bolus injections of phenylephrine was compared in deoxycorticosterone acetate (DOCA) -salt sensitive and normotensive rats. Osmotic minipumps that dispensed either nicotine (2.4 mg/kg/day) or saline were implanted in DOCA and normotensive rats for
more » ... rmotensive rats for 18 days. Anesthetized DOCA-nicotine, DOCAsaline, control-nicotine, and control-saline rats had mean arterial pressures (MAP) of 117±3, 110±9, 90±3, and 89±5 mm Hg, respectively. Nicotine decreased the sensitivity (p<0.05) of baroreceptor reflex control of RNA (%ARNA/AMAP) in the DOCA-nicotine rats (-0.92 ±0.08) compared with the DOCA-saline (-1.44±0.16), control-nicotine (-1.45±0.08), or controlsaline (-1.45 ±0.21) rats. The reflex decrease in respiratory activity (%AMDA/AMAP x 100) was impaired (p<0.01) in both control-nicotine (-24.5±33) and DOCA-nicotine (-18.2±4.6) rats compared with control-saline (-59.2±9.1) and DOCA-saline (-52.5±9.9) rats. The reflex decrease in heart rate (absolute AHR/AMAP) in both DOCA-nicotine (1.56±0.17) and control-nicotine (1J54±O.24) rats was augmented compared with DOCA-saline and controlsaline rats (0.91 ±0.12 and 0.97±0.14). Thus, chronic nicotine impairs reflex control of RNA in response to increases in arterial pressure only in DOCA-salt hypertensive rats, whereas nicotine impairs reflex respiratory activity and augments the reflex decrease in heart rate in normotensive and hypertensive rats. (Hypertension 1991;17:179-186)
doi:10.1161/01.hyp.17.2.179 pmid:1991650 fatcat:s2sphcg5tfhqxgk65s6r7avsmm