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Effect of subconvulsive doses of bicuculline on the incorporation of radioactive precursors into glycerolipids in rat brain areas

  • Arienti G. 
  • Piccinin G. L. 
  • Ramacci M. T. 
  • Corazzi L. 
Original Articles

Abstract

Bicuculine (either 25 μmol or 12.5 μmol/kg body wt) was administered to rats by intraperitoneal route. Animals treated with 25 μmol/kg experienced convulsions, whereas those receiving 12.5 μmol/kg did not. Controls received saline instead of the drug. Radioactive precursors [2-3H] glycerol and/or [1,214C] ethanolamine were injected into cerebral ventriculi simultaneously with bicuculline and the rats were killed 12 min afterwards. Their brains were dissected by hand into four parts (cerebellum, brain stem, hippocampus, cerebral cortex) and the labeling of lipid classes determined after extraction and separation.

Although glycerol was incorporated into lipid better than ethanolamine in all areas, the fate of the injected radioactive precursors varied according both to area and treatment. The lowest uptake of radioactivity was in the cerebral cortex and the highest in the brain stem and hippocampus. Moreover, the administration of bicuculline influenced the distribution of radioactivity among lipid classes; these variations, however, were not dependent on the administered doses of bicuculline. We conclude that the effects on glycerolipid metabolism observed in convulsing animals are due to several causes including alterations of systemic parameters (hypertension, hypoxia, etc.). The distribution of glycerol label between phospholipid and neutral lipid is proposed as a biochemical model for the study of convulsive and subconvulsive states.

Key-Words

Phospholipid diglyceride bicuculline convulsions brain 

Sommario

Si somministrava ai ratti bicucullina in ragione di 25 μmoli o di 12.5 μmoli/kg di peso corporeo. Gli animali trattati con la dose più elevata del convulsivante avevano convulsioni, mentre quelli trattati con 12,5 μmoli/kg non ne avevano. Ai controlli si somministrava NaCl al 9‰. I precursori radioattivi ([2-3H]glicerolo e/o [1,214C] etanolammina) venivano iniettati nei ventricoli cerebrali contemporaneamente alla bicucullina ed i ratti sacrificati 12 min più tardi. I cervelli erano quindi prelevati e divisi in quattro parti (cervelletto, corteccia cerebrale, ippocampo e tronco cerebrale). La marcatura delle classi lipidiche era determinata dopo estrazione e separazione.

Sebbene il glicerolo fosse incorporato in lipidi meglio dell'etanolammina in tutte le aree, il destino del precursore iniettato variava sia in relazione all'area che al trattamento. L'assunzione di radioattività era massima nel tronco e nell'ippocampo e minima nella corteccia cerebrale. La somministrazione di bicucullina influenzava la distribuzione della radioattività fra le classi lipidiche; tuttavia queste variazioni non dipendevano dalle dosi del convulsivante. Le alterazioni sistemiche che accompagnano le convulsioni (ipossia, ipertensione, ecc.) sembrano dunque rilevanti nel determinare il tipo di modificazione del metabolismo lipidico.

Viene proposta la distribuzione di marcatura del glicerolo tra fosfolipidi e lipidi neutri come un parametro per studiare gli stati convulsivi e subconvulsivi.

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Copyright information

© Masson Italia Periodici 1989

Authors and Affiliations

  • Arienti G. 
    • 1
  • Piccinin G. L. 
    • 2
  • Ramacci M. T. 
    • 3
  • Corazzi L. 
    • 1
  1. 1.Dipartimento di Medicina Sperimentale e Scienze BiochimicheUniversità degli Studi di PerugiaPerugia
  2. 2.Divisione di NeurologiaOspedale di PerugiaPerugia
  3. 3.Laboratori di Ricerca Sigma-TauPomeziaPerugia

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