Nicotine impairs reflex renal nerve and respiratory activity in deoxycorticosterone acetate-salt rats.
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 18 days. Anesthetized DOCA-nicotine, DOCA-saline, 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 less than 0.05) of baroreceptor reflex control of RNA (% delta RNA/delta MAP) 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 control-saline (-1.45 +/- 0.21) rats. The reflex decrease in respiratory activity (% delta MDA/delta MAP x 100) was impaired (p less than 0.01) in both control-nicotine (-24.5 +/- 3.3) 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 delta HR/delta MAP) in both DOCA-nicotine (1.56 +/- 0.17) and control-nicotine (1.54 +/- 0.24) rats was augmented compared with DOCA-saline and control-saline rats (0.91 +/- 0.12 and 0.97 +/- 0.14).(ABSTRACT TRUNCATED AT 250 WORDS)
Whitescarver
S A
SA
Department of Physiology and Biophysics, School of Medicine, University of Louisville, Ky 40292.
Roberts
A M
AM
Stremel
R W
RW
Jimenez
A E
AE
Passmore
J C
JC
D000818:Animals; D001794:Blood Pressure; D003900:Desoxycorticosterone; D006339:Heart Rate; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D007668:Kidney / Q000294:innervation*; D008297:Male; D009424:Nervous System Physiological Phenomena; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000502:physiology*; D012119:Respiration / Q000187:drug effects*; D012965:Sodium Chloride
D003900:Desoxycorticosterone; D012965:Sodium Chloride; D009538:Nicotine