[Methods for intracerebral injection].

In behavioral studies, seeking the regional site of action of centrally acting drugs, injections are normally made directly into a restricted area of the brain using a microsyringe inserted in a guide cannula that had been implanted previously. This paper describes conventional methods for injecting a drug into the rat brain. The common technique used in brain dialysis studies is to apply the drugs focally into the brain by infusing them through the dialysis probe. One of the main problems of this technique is the difficulty in estimating actual doses of the drugs administered. The present paper also describes a microdialysis probe in combination with a microinjection tube to examine changes in the release and metabolism of dopamine within the area where the drugs were injected under experimental conditions similar to those used in behavioral studies. Using this method, we demonstrated the characteristic difference between two benzamide D2-receptor antagonists YM-09151-2 and l-sulpiride on dopamine release in rat striatum.