Neuropeptide Y and behaviour: effects of intrastriatal NPY on circling behaviour of rats

Neuropeptide Y (NPY) is a member of the pancreatic polypeptide family and consists of 36 amino acids, sharing sequence homologies with the putative gut hormone peptides YY and PP. NPY dose-dependently stimulates food intake when administered icv into the paraventricular hypothalamic nucleus of rats. Icv NPY has also been reported to decrease locomotor activity, rearing and grooming behaviour. Little behavioural research focusing on other unconditioned behaviours has been conducted. However, intrastriatal injections of NPY have been shown to increase dopamine (DA) turnover there. As unilateral manipulations of central DA result in turning away from the side of higher DA activity, it is of interest to evaluate the effects of intrastriatal NPY on this behaviour. Preliminary results indicate that NPY produces a significant contralateral turning bias when injected directly into the striatum. This raises the intriguing possibility that contralateral turning induced by intrastriatal NPY may be mediated by DA.