Suppression Of Exploratory Behavior Research Articles

Interaction between purine and benzodiazepine: Inosine reverses diazepam-induced stimulation of mouse exploratory behavior.

Inosine, 2-deoxyinosine, and 2-deoxyguanosine completely reversed the increase in exploratory activity elicited in mice by diazepam. The inhibition of exploratory behavior by purines occurred at doses that when given alone have no effect on exploratory behavior. 7-Methylinosine, which does not bind to the brain benzodiazepine binding site in vitro, had no effect on the diazepam-induced increase in exploratory behavior. Behavioral effects produced by various combinations of inosine and diazepam indicate that the interaction between purine and benzodiazepine is antagonistic and support the hypothesis that the naturally occurring purines function in anxiety-related behaviors that respond to benzodiazepine treatment.

The effect of beta-alanine on motor behaviour, body temperature and cerebral monoamine metabolism in rat.

Intracerebroventricular (ICV) injection of beta-alanine produced a decrease in rectal temperature, inhibition of exploratory behaviour and motility, and changes in the metabolism of cerebral monoamines. Dopa and 5-HTP accumulation after inhibition of L-aromatic amino acid decarboxylase, NSD 1015 (3-hydroxybencylhydrazine HCl, 100 mg/kg i.p.) was found to be significantly increased in all the dissected cerebral regions of animals treated with beta-alanine, as compared to the controls. Levels of tyrosine and tryptophan did not show any significant change. Endogenous levels of dopamine (DA), noradrenaline (NA), serotonin (5-HT) and 5-hydroxyindolacetic acid (5-HIAA), did not change. After inhibition of the catecholamines synthesis with alpha-methyltryrosine (alpha-MT), dopamine depletion was retarded and noradrenaline accelerated, but without reaching statistical significance. After intraperitoneal (i.p.) injection of beta-alanine, significant changes in motor behaviour were found. Body temperature and metabolism of brain catecholamine were unchanged. This lack of effect could be explained by poor penetration through the blood-brain barrier.

Conditioned inhibition of exploration in young rats

The inhibition of exploratory behavior, and responses to the CS were used as measures of conditioned fear in young rats. Comparisons with control groups indicate that any experience with shock produces equal amounts of fear retention in the early and middle stages of extinction. The differential effects produced by the various procedures became apparent only later in extinction when the group that had experienced CS-US pairings in acquisition exhibited significantly more residual fear than the controls on both response measures.