Effects of benztropine on ketamine-induced behaviors in Cebus monkeys

Y. Shiigi, Daniel Casey

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, causes a schizophrenic-like psychosis in normal volunteers and exacerbates psychotic symptoms in patients with schizophrenia. Recent work has shown that ketamine and other NMDA antagonists affect a range of behaviors in nonhuman primates, particularly those associated with motor and mental function such as attention and perception. Several lines of study also suggest that NMDA antagonists interact with cholinergic mechanisms. The effects of benztropine, an anticholinergic agent, on ketamine-induced behaviors were evaluated in a double-blind randomized test design in 20 Cebus monkeys. Benztropine (0.05, 0.1 and 0.25 mg/kg, i.m.) was injected 1 hour before ketamine (2.5 and 5.0 mg/kg, i.m.) administration. Behaviors scored for 90 minutes after ketamine administration included salivation, dystonia and reactivity to external stimuli. Benztropine almost completely blocked ketamine-induced hypersalivation, and partially ameliorated the dystonia syndrome by 50%, but did not affect ketamine-induced decreased reactivity to external stimuli. These results suggest that cholinergic mechanisms only moderately influence ketamine-induced central nervous system effects of motor dysfunction, and may not play a substantive role in the ketamine-induced deficit of reactivity to external stimuli, which involves a complex interaction of mental functions such as attention and perception, as well as motor behavior.

Original languageEnglish (US)
Pages (from-to)293-298
Number of pages6
JournalBehavioural Pharmacology
Volume12
Issue number4
StatePublished - 2001

Fingerprint

Benztropine
Cebus
Ketamine
Haplorhini
Dystonia
N-Methylaspartate
Cholinergic Agents
Sialorrhea
Salivation
Excitatory Amino Acid Antagonists
Cholinergic Antagonists
N-Methyl-D-Aspartate Receptors
Psychotic Disorders
Primates
Schizophrenia
Healthy Volunteers
Central Nervous System

Keywords

  • Anticholinergics
  • Behavior
  • Benztropine
  • Cebus monkey
  • Ketamine
  • NMDA
  • Nonhuman primates

ASJC Scopus subject areas

  • Pharmacology
  • Neuroscience(all)

Cite this

Effects of benztropine on ketamine-induced behaviors in Cebus monkeys. / Shiigi, Y.; Casey, Daniel.

In: Behavioural Pharmacology, Vol. 12, No. 4, 2001, p. 293-298.

Research output: Contribution to journalArticle

Shiigi, Y. ; Casey, Daniel. / Effects of benztropine on ketamine-induced behaviors in Cebus monkeys. In: Behavioural Pharmacology. 2001 ; Vol. 12, No. 4. pp. 293-298.
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