Biomedical subjects

D Lecca

Publications and source records attributed to D Lecca.

3 recordsLinked to original sources

PubMed1992

Decrease in GABAergic function induced by pentylenetetrazol kindling in rats: antagonism by MK-801.

The role of tau-aminobutyric acid (GABA)A receptors and of the N-methyl-D-aspartate (NMDA) subtype of excitatory amino acid receptors was studied in the pentylenetetrazol (PTZ) kindling model. The repeated administration of subconvulsant doses of PTZ (30 mg/kg i.p., 3 times a week for up to 10 weeks) produced chemical kindling in 80% of rats under treatment. PTZ kindling was associated with a decrease in GABA-mediated inhibition in the central nervous system. Thus, the binding of [3H]GABA, the binding of 35S-t-butylbicyclophosphorothionate and the GABA-stimulated uptake of 36Cl- were significantly decreased in the cerebral cortex of PTZ-kindled rats as compared with control rats chronically treated with saline. Moreover, PTZ-kindled rats showed a persistent increase in the sensitivity to the convulsant action of different GABA function inhibitors, such as isonicotinic acid hydrazide (120 mg/kg s.c.), picrotoxin (1.5 mg/kg i.p.), bicuculline (1.3 mg/kg s.c.), FG 7142 (N-methyl-beta-carboline-3-carboxamide; 20 mg/kg i.p.) and Ro 15-4513 (ethyl-8-azido-5,6-dihydro-5-methyl-6-oxo-4H- imidazo-(1,5-a) (1,4)-benzodiaze pine-3-carboxylate; 20 mg/kg i.p.). The pretreatment with the noncompetitive NMDA receptor antagonist, MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-imine maleate; 0.1-1.0 mg/kg i.p., 40 min before each injection of PTZ], prevented in a concentration-dependent manner the development of kindling and the increase in the responsiveness to the convulsant effects of GABA function inhibitors observed in PTZ-kindled rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

MK-801 prevents chemical kindling induced by pentylenetetrazol in rats.

The repeated administration of pentylenetetrazol (PTZ) at a subconvulsant dose (30 mg/kg i.p., three times a week for nine weeks) produced kindling in 90% of rats under treatment. Pretreatment with the N-methyl-D-aspartate receptor antagonist, MK-801 (1 mg/kg i.p., 40 min before PTZ), prevented the behavioral manifestation (i.e. motor seizures) as well as the development of kindling. In fact, convulsions were not observed in rats pretreated with MK-801 either during the chronic PTZ administration or when challenged with PTZ three and 10 days after completion of the chronic treatment. The results suggest an involvement of excitatory amino acid neurotransmission in PTZ kindling.

Amino Acids↗

PubMed1991

Pentylenetetrazol-induced kindling in rats: effect of GABA function inhibitors.

The repeated administration of subconvulsant doses of pentylenetetrazol (PTZ) produced a progressive sensitization to the effects of this compound (i.e., chemical kindling) in the rat. A very similar time-course for PTZ-induced kindling was observed using two different treatment schedules: 1) one injection every day (30 mg/kg, IP), and 2) one injection (30 mg/kg, IP) every second day. When these treatment schedules were used for eight consecutive weeks, more than 80% of the rats displayed convulsions by the end of treatment. In contrast, only 20% of the rats were sensitized if PTZ was administered twice daily at the dose of 15 mg/kg, IP. The increased sensitivity to the convulsant effect of PTZ was still present one year after completion of the chronic treatment. Moreover, rats kindled with PTZ showed an enhanced susceptibility to convulsions induced by different inhibitors of central GABAergic function, such as the chloride channel blocker picrotoxin, the benzodiazepine receptor ligands FG 7142 and Ro 15-4513, and the inhibitor of GABA synthesis isoniazid. In contrast, the sensitivity to the convulsant action of the glycine receptor antagonist strychnine was unchanged by repeated PTZ administration. It is suggested that kindling produced by PTZ may be associated with a persistent reduction in the inhibitory function of the GABAergic system in the brain.

Animals↗