68 Pharmacological Research, Vol. 26, Supplement I, 1992

DOPAMINE D2 RECEPTOR GENE EXPRESSION IN MMQ CELLS AND FUNCTIONAL CHARACTERIZATION OF RELATED TRANSDUCING MECRANISMS Cannel0 Ventra, Tullio Florio, Maurizio Grimaldi, Olimpia Meucci, Saverio Talia, Gennaro Schettini and Adrian0 Marina. Dipartimento di Scienza delle Comunicazioni Umane, Sezione di Farmacologia, II Facolta' di Medicina, Universita'di Napoli.

The M M Q cell line, recently isolated from the 7315a transplantable rat pituitary tumor, secretes prolactin and expresses a native and functional dopamine (DA) D2 receptor. These properties make this cell line an useful model to study the D2 receptor, acting via its native environment".

"coupling The purpose of our study has been to evaluate a

possible functional diversity of this receptor in comparison with that expressed in anterior pituitary lactotrophes and with that transfected in GH4Cl cells (GH4ClZ-R7). In membranes derived from these cells, transducing

we have extensively analyzed the mechanisms mediating the effect of DA on basal

and stimulated (Forskolin, NaF, MnC12) adenylate cyclase (AC) activity, with particular regard to the interaction between this receptor and GTP-binding protein/s, presumably the Gi-alpha2, by using GTP and its non-hydrolyzable analogues, such as GTP-gamma-S and Gpp(NH)p. The modulation of DA D2 receptor-gene expression by various stimuli, acting via different second messengers activated pathways, under evaluation. (CNR grant no 9003204 to G.S.)

is currently

EFFECTS OF ANTICONVULSANTS ON HYPOXIA-INDUCED EPILEPTIFORM BURSTING AND FUNCTIONAL ELECTRICAL FAILURE IN RAT HIPPOCAMPAL SLICES. FRANK C., DOMENICI M-R., SAGRATELLA S., SCOTT1 de CAROLIS A. PHARMACOLOGY DEPARTMENT, ISTITUTO SUPERIORE DI SANITA', ROMA

In the present work the influence of various anticonvulsants, affecting different neurotransmitter systems, has been investigated on the hypoxia-induced epileptiform bursting and functional electrical failure in rat hippocampal slices subjected to a 45 min hypoxic period. The incidence of appearance of the hypoxia-induced or post-hypoxic epileptiform bursting was significantly decreased (P<O.O5) by 5,5- diphenylhydantoin (100 pM), and by the N-methyl-D-aspartate (NMDA) antagonist dizocilpine (MX 801, 50 pM), while it was not affected by pentobarbitone (75 pM) and by the adenosine agonist N8-(L-2-phenylisopropyl)adenosine (L-PIA, 0.5 FM). The incidence of reappearance of the CA1 population spike after hypoxia was significantly increased (Pt0.05) by 5,5- diphenylhydantoin (lOOpM), and ME 801 (50 pM), while it was not affected by pentobarbitone (75 pM) and L-PIA (0.5 PM). The results suggest a different useful role of anticonvulsants in the treatment of hypoxia-induced functional disturbances.