Apomorphine-induced circling behaviour in hamsters following unilateral injection of scrapie gent in the striatum.

Twenty golden hamsters received a microinjection of scrapie agent into the left striatum. At different times after inoculation animals were injected intraperitoneally with apomorphine, a direct dopamine receptor agonist. Two types of effects developed simultaneously, starting at about 80 days after infection. First, apomorphine induced a rotational behaviour which showed a progressive destruction of the striatal neurones at the site of injection. This suggest a local spread of scrapie agent by cell to cell transfer in the striatum. Secondly, the clinical signs of scrapie developed, indicating a more widespread distribution of agent throughout the brain.