ISSN:
1432-2072
Keywords:
Apomorphine
;
Gnaw compulsion
;
Antihistamines
;
Cholinergic mechanism
;
Methysergide
;
p-Chlorophenylalanine
;
Catecholaminergic mechanism
;
Mice
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract In mice, apomorphine (10 mg/kg s.c.) does not induce a compulsion to gnaw, but pretreatment with antihistamines, viz. pheniramine, chlorpheniramine and mepyramine, in doses ranging from 30 to 60 mg/kg i.p. caused gnawing activity. Mepyramine showed significantly less effect when compared to the other two agents. Antihistamines are known to influence the activity of biogenic amines in central nervous system. The potentiation of apomorphine-induced gnawing by antihistamines might depend upon the reciprocal balance between dopaminergic and cholinergic systems. This was tested by blocking biosynthesis of biogenic amines or by blocking their receptors. The potentiation of gnawing was antagonised by physostigmine (0.25 mg/kg) or blocked by pretreatment with α-methyl-p-tyrosine (α-MPT) (4×5 mg/kg) and bis-(4-methyl-1-homopiperazinyl-thiocarbonyl)-disulphide (FLA) (40 mg/kg), while p-chlorophenyl alanine (p-CPA) (3×100 mg/kg) had no effect. Similarly, phenoxybenzamine (30 mg/kg) and haloperidol (1.0 mg/kg) inhibited gnawing activity, but methysergide (10 mg/kg) had no effect. Furthermore, pretreatment with tetrabenazine (20 mg/kg) and l-Dopa (200 mg/kg) did not affect gnawing activity. It is concluded that both pheniramine and chlorpheniramine potentiate apomorphine gnawing by upsetting the cholinergic and dopaminergic balance in favour of dopaminergic dominance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00423299
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