A study on the development of barbiturate tolerance and dependence in hamster glial cells in culture

Abstract

Hamster astroblast glial cells (clone NN) in cell culture were exposed to from 1 × 10 −5 to 3 × 10 −3 M pentobarbital-Na and from 1 × 10 −5 to 2·5 × 10 −4 M morphine hydrochloride for various periods of time. Profound morphological changes were induced in a dose/time-related fashion by pentobarbital only. These consisted of growing of cellular expansions, parallel cellular arrangement and increased amounts of intracellular material. Exposure of the cells to morphine up to 6 weeks resulted in a dose-correlated decreased rate of proliferation, but no specific morphological alteration could be observed. The morphological changes induced in cultured glial cells by pentobarbital were accompanied by an increase in oxygen consumption (35–45%) as well as an increase in glucose uptake (90–110%). These effects were compared to those obtained with bromodeoxyuridine which affected glucose metabolism similarly. Furthermore, glial cells that had been treated for 4 weeks with the barbiturate were less sensitive to the depression of oxygen consumption by a challenging dose of pentobarbital-Na signifying the development of cellular tolerance. After having cultured the cells in barbiturate for 4, 9 or 14 weeks, normal medium was substituted. This resulted in severe degenerative changes and cell deaths as well as altered growth characteristics in the surviving cells, demonstrating some degree of cellular dependence on the barbiturate. In addition, cross-tolerance with ethyl alcohol was established since it could be substituted for the barbiturate without the occurence of degenerative changes.