Relationship between the central stimulation of atropine and cholinergic system
Bian, C.F.; Ye, M.; Xing, S.H.; Teng, Y.D.; Xu, P.C.
Zhongguo Yao Li Xue Bao 6(3): 149-151
1985
ISSN/ISBN: 0253-9756 PMID: 2874686 Document Number: 263123
The spontaneous activity of mice increased after atropine 5 mg/kg ip, and decreased when atropine was combined with hemicholininium 0.2 mg/kg icv, physostigmine 0.5 mg/kg ip, diazepam 10 mg/kd ip or phenobarbital 100 mg/kg ip, respectively. The activity of mice was increased when atropine was combined with 4-aminopyridine 5 mg/kg ip. In rabbits, 5-10 min after icv atropine 1 mg/kg, paroxysmal convulsions and tonic spasm were seen. EEG revealed low voltage and rapid waves; seizure high voltage spinal waves (1-2 c/s and 10-20 c/s) and 70% rabbits died. If hemicholine 100 .mu.g/kg icv was given 24 h beforehand or scopolamine 3 mg/kg icv was used together with atropine, central stimulation became less intense, but 4-aminopyridine 1 .mu.g/kg icv increased its effect. Physostigmine 0.3 mg/kg iv, contrast to that in mice, did not alter the central stimulation of rabbits, but diazepam 2 mg/kg iv and phenobarbital 60 mg/kg iv antagonized atropine very well. These results suggest that the central excitatory effect of atropine may be attributed to the blockage of inhibitory muscarinic receptors and enhancement of ACh releasing in brain.