Hypotensive action of cycleanine dimethobromide
Abstract
The nervi splanchnici major of 10 dogs were cut and the distal ends were stimulated. The hypertensive effect was markedly diminished or abolished after iv cycleanine dimethobromide 1-2 mg/kg. The hypotensive effects from the electrical stimulation at the distal ends of left vagi in 3 bilaterally vagotomized dogs was greatly diminished or abolished after iv 2-3 mg/kg.
The histamine levels in arterial blood of 9 dogs rose from 19+/-(SD) 6 ng/ml to 227+/-203 ng/ml after iv 1 mg/kg.
Twelve rabbits were given iv the drug and monitored by ECG. In 2 rabbits SAB II* developed after 1 mg/kg (in 3 s), AVB III* and ventricular escape appeared in one and auricular extrasystole in the other rabbit. In 10 rabbits given 0.75 mg/kg in 3 s, only the sinus rates showed some diminution. Five minutes later an additional dose of 0.75 mg/kg was given iv in 3 s in 6 out of the 10 rabbits. All these 6 rabbits manifested SAB II*, while 1 rabbit showed AVB I* and ventricular escape, and another rabbit developed ventricular extrasystole. In 2 rabbits the additional doses were 1.25 and 1.50 mg/kg, respectively and iv slowly in 20 min. The sinus rates decreased progressively.
The contraction amplitudes of 7 isolated rabbit hearts were not augmented or even diminished by cycleanine dimethobromide 200 mg/L.
So the ganglionic blocking effect plays an important role in the mechanism of the hypotensive action.
Keywords:
The histamine levels in arterial blood of 9 dogs rose from 19+/-(SD) 6 ng/ml to 227+/-203 ng/ml after iv 1 mg/kg.
Twelve rabbits were given iv the drug and monitored by ECG. In 2 rabbits SAB II* developed after 1 mg/kg (in 3 s), AVB III* and ventricular escape appeared in one and auricular extrasystole in the other rabbit. In 10 rabbits given 0.75 mg/kg in 3 s, only the sinus rates showed some diminution. Five minutes later an additional dose of 0.75 mg/kg was given iv in 3 s in 6 out of the 10 rabbits. All these 6 rabbits manifested SAB II*, while 1 rabbit showed AVB I* and ventricular escape, and another rabbit developed ventricular extrasystole. In 2 rabbits the additional doses were 1.25 and 1.50 mg/kg, respectively and iv slowly in 20 min. The sinus rates decreased progressively.
The contraction amplitudes of 7 isolated rabbit hearts were not augmented or even diminished by cycleanine dimethobromide 200 mg/L.
So the ganglionic blocking effect plays an important role in the mechanism of the hypotensive action.