Effect of pimobendan on cardiopulmonary baroreflex control of sympathetic nerve activity in healthy young men.
In order to determine the effect of pimobendan on sympathetic nerve activity and cardiopulmonary baroreflex (CPB), electrocardiogram, direct arterial pressure, central venous pressure (CVP) and cardiac output were recorded along with muscle sympathetic nerve activity (MSNA) in 8 healthy young men. CPB function was evaluated before and 60 min after oral administration of 5 mg pimobendan using the response of MSNA to lower body negative pressure (LBNP) of -5 and -10 mm Hg. The same protocol also was performed during handgrip exercise. Cardiac index, MSNA increased and CVP decreased significantly (p<0.01, respectively), but arterial pressure and heart rate unchanged after pimobendan administration. During LBNP, CVP decreased and MSNA increased significantly. CPB sensitivity was augmented from 5.53+/-0.75 to 8.59+/-0.78 burst incidence/mm Hg after pimobendan administration (p<0.01). Pimobendan did not alter the percentage increase of MSNA during handgrip exercise. In conclusion, pimobendan induces an increase in basal sympathetic nerve activity by decreasing CVP and augmenting CPB sensitivity without changing arterial pressure in healthy young men.
Maruyama
Michiro
M
Department of Internal Medicine, Kanazawa University, Japan. michirom@medf.m.kanazawa-u.ac.jp
Takamura
Masayuki
M
Takata
Shigeo
S
Murai
Hisayoshi
H
Usui
Soichiro
S
Furusho
Hiroshi
H
Sakagami
Satoru
S
Yuasa
Toyoshi
T
Shimakura
Atsuhiro
A
Kaneko
Shuichi
S
D000328:Adult; D017704:Baroreflex / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D011724:Pyridazines / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000187:drug effects*
D002316:Cardiotonic Agents; D011724:Pyridazines; C041648:pimobendan