IMPLANTS FOR SUSTAINED DRUG-RELEASE OVER THE SOMATOSENSORY CORTEX OF THE NEWBORN RAT - A COMPARISON OF MATERIALS AND SURGICAL-PROCEDURES

Drugs that interfere with neural transmission are an important tool in assessing the role of specific neurotransmitters in the development o f the nervous system. Systemic drug treatments often produce neurodeve lopmental effects with questionable specificity. Furthermore, many com pounds of interest do not cross the blood-brain barrier. To overcome t hese limitations, either elvax or gelfoam implants have been previousl y employed to produce sustained drug release over specific brain regio ns. In this paper, stereotaxic coordinates are provided for reproducib le insertion of drug-delivery systems over the rat somatosensory corte x at birth (P0), prior to the appearance of the cortical barrel patter n; a novel and simpler method for preparation of elvax 40p sheets is d escribed; a new implantation technique is provided. Furthermore, we co mpare the efficiency and tolerability of elvax vs gelfoam implants. sh owing that gelfoam, but not elvax, significantly disrupts cortical cyt oarchitecture. Finally, successful destruction of serotonin-containing terminals in layer IV of the primary somatosensory cortex of the newb orn rat is demonstrated by application of parachloroamphetamine-contai ning elvax implants. (C) 1997 Elsevier Science B.V.