[Comparison of endocrine effects of hypotension induced by sodium nitroprusside, trimetaphan camsylate and a nitroprusside-trimetaphan mixture in rabbits].
Endocrine effects of hypotension induced by nitroprusside, trimetaphan and a nitroprusside-trimetaphan mixture were studied in 34 male rabbits under halothane anesthesia. They were randomly divided into four groups; nitroprusside (group N; n = 8), trimetaphan (group T; n = 10), a nitroprusside-trimetaphan mixture (group M; n = 8) and controls (group C; n = 8). No change was noted in plasma catecholamines measured in group C throughout the experiment, but plasma renin activity decreased progressively. During induced hypotension, plasma catecholamines and plasma renin activity of group N were significantly higher than the control value. In contrast, in group T plasma epinephrine decreased significantly. On the other hand, in group M, plasma renin activity showed a slight but not significant increase, while plasma catecholamines remained unchanged. This may have occurred since a mixture of nitroprusside and trimetaphan produced the dissociation of renin-angiotensin-sympathoadrenal loop. In conclusion, these results suggest that a nitroprusside-trimetaphan mixture is a useful method for hypotensive anesthesia by inhibiting the excessive activation of renin-angiotensin-sympathetic system.
Takeda
S
S
Inada
Y
Y
Tomaru
T
T
Kagawa
T
T
Ikeda
T
T
Mozawa
N
N
Morimoto
F
F
D000818:Animals; D004338:Drug Combinations; D004837:Epinephrine / Q000097:blood; D005292:Ferricyanides; D007023:Hypotension, Controlled; D009599:Nitroprusside / Q000008:administration & dosage*; D009638:Norepinephrine / Q000097:blood; D011817:Rabbits; D012083:Renin / Q000097:blood; D014294:Trimethaphan / Q000008:administration & dosage*
D004338:Drug Combinations; D005292:Ferricyanides; D009599:Nitroprusside; D014294:Trimethaphan; D012083:Renin; D009638:Norepinephrine; D004837:Epinephrine