[The characteristics of the cholinergic mechanisms of the nucleus accumbens and the caudate nucleus in regulating an instrumental escape reflex in dogs].

We perform comparative analysis of the involvement of dorsal (Neostriatum) and ventral (Nucleus Accumbens) striatal cholinergic systems in the regulation of defensive instrumental reflex, connected with the maintenance of certain flexor posture, in dogs. The data obtained show that the carbachol microinjections (0.05 mkg) into the contralateral Head of Caudate Nucleus significantly improved instrumental reflex due to increasing of a tonic movement component and inhibition of interstimulus and phasic leg raising. In was shown that the cholinergic system of Neostriatum was of great importance for the regulation of the main component of postural adjustment: the unloading of the working limb. The same microinjections into Nucleus Accumbens significantly improved (ipsi- and contralaterally) the instrumental reflex due to prolonged increasing of a phasic component of movement and its amplitude. It can be suggested that the Neostriatum cholinergic system is structurally included into the motor components realization of instrumental reflex, connected with a certain posture maintenance. The activation of cholinergic system of Nucleus Accumbens affects this form of behavior in an excitatory way, being of nonspecific and prolonged character.