Fujiko Sanae (1), Hisao Hayashi (1), Keigo Chisaki (2) and Yasuhiro Komatsu
(2)
(1) Department of Medicine, Faculty of Pharmaceutical Sciences, Hokuriku
University, Ho-3 Kanagawa-machi, Kanazawa 920-1181, Japan
(2) Department of Safety and Drug Metabolism, Central Research Laboratories,
Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192,
Japan
Abstract: Effects of Saiko-ka-ryukotsu-borei-to (SRBT) on theophylline-induced
tachycardia in anesthetized rats and theophylline-induced locomotion and
convulsions in mice were examined. An intraduodenal administration of SRBT
(1 g/kg) prevented theophylline (5 mg/kg, i.v.)-induced tachycardia in rats.
SRBT also attenuated an increase in arterial blood pressure with a slow
reduction in heart rate of rats treated with theophylline, with no influence
on the plasma level of theophylline. However, SRBT did not change the beating
rate of right atrium isolated from rats in the absence or presence of theophylline
or isoproterenol. The locomotor activity of theophylline in mice was reduced
by the treatment with SRBT. Furthermore, the latency of convulsions in mice
induced by administration of theophylline at a higher dose (240 mg/kg, i.p.)
was prolonged by treatment with SRBT (1 g/kg, p.o.) and seven out of fifteen
mice were saved from death due to convulsions. These results suggest that
theophylline-induced tachycardia and central nervous stimulation are suppressed
by SRBT and that SRBT may reduce the undesirable actions of theophylline
on the cardiovascular and central nervous systems.
Keywords: Theophylline, Saiko-ka-ryukotsu-borei-to, Heart rate, Locomotor
activity, Convulsion