EFFECT OF PERTUSSIS TOXIN ON THE RESPONSE OF RAT MEDIAL PREFRONTAL CORTEX CELLS TO THE IONTOPHORESIS OF SEROTONIN RECEPTOR AGONISTS

In this study, we examined the response of spontaneously active as wel l as quiescent cells (L-glutamate-activated) in the rat medial prefron tal cortex (mPFc) to the iontophoresis of 2-methylserotonin (2-Me-5-HT , 5-HT3 receptor agonist), (+/-)-2,5-dimethoxy-(4-iodo-phenyl)-2-amino propane (DOI, 5-HT2A,2C receptor agonist), 8-hydroxy-N,N-di-propylamin o tetralin (8-OH-DPAT, 5-HT1A receptor agonist) and gamma-aminobutyric acid (GABA, a non-selective GABA receptor agonist) after the intracer ebral administration of pertussis toxin, an inactivator of the G(i/o) protein. This was accomplished using the techniques of extracellular s ingle cell recording and iontophoresis. The administration of pertussi s toxin (0.5 mug, 24 hours before the experiment) into the mPFc did no t alter the response of mPFc cells to the iontophoresis of DOI, 2-Me-5 HT or GABA compared to saline treated controls. However, the response of mPFc cells to the iontophoresis of 8-OH-DPAT was significantly atte nuated in the animals pretreated with pertussis toxin compared to cont rols. These results suggest that the 5-HT1A but not 5-HT2A, 2C or 5-HT 3 receptor is coupled to the G(i/o) protein.