Effects of alpha-2 adrenoceptor antagonists on rough-and-tumble play in juvenile @entity35 : evidence for a site of action independent of non-adrenoceptor XXXX binding sites.

@entity3159 @entity9006 @entity23190 @entity35 @entity947 @entity29749
The pharmacological specificity of alpha-2 adrenoceptor involvement in the modulation of rough-and-tumble play behavior was assessed in juvenile @entity35 . The alpha-2 adrenoceptor antagonists @entity9006 and @entity23190 both increased the frequency of pinning in individually housed @entity35 that were given a brief opportunity to play. Dorsal contacts, a measure of play solicitation, were not consistently affected by these compounds. Since @entity23190 shows little affinity for non-adrenoceptor @entity947 binding sites, it is likely that the facilitation of play following administration of these two compounds is due to blockade of alpha-2 receptors. The effect of @entity23190 and @entity9006 is unlikely to be an artifact associated with using @entity35 that are reared in isolation, as @entity23190 also increased pinning, as well as dorsal contacts, in group-housed @entity35 that were isolated for a short period (4h) before the play session. The alpha-1 adrenoceptor antagonist @entity3159 , which also binds to alpha-2B receptors, reduced the frequency of both pinning and dorsal contacts. There was a strong trend for @entity29749 , a centrally active alpha-1 agonist, to attenuate the effect of @entity3159 on play. While this leaves open the possibility that @entity3159 may be reducing play through alpha-1 blockade, antagonist activity at alpha-2B receptors cannot be ruled out. From these data, we conclude that the facilitation of play following @entity9006 and @entity23190 is likely due to blockade of alpha-2A adrenoceptors. These findings add further support for a specific role of alpha-adrenoceptors in the modulation of playfulness in the juvenile @entity35 .
