Effect of Δ9 tetrahydrocannabinol on cyclic nucleotides in synchronously dividing Tetrahymena

Abstract

Cyclic nucleotide levels were determined in division-synchronized Tetrahymena and the effect of Δ9-tetrahydrocannabinol (THC) on the cyclic nucleotide levels was studied. In non-drug-treated division-synchronized cells, there was no statistically significant variation in the level of cAMP and cGMP during the G2 period, preceding the first division. During the free running cell cycle (the interval of time between the first and second synchronous division) the twofold increase in the level of cAMP was statistically significant; however the variation in the level of cGMP was not statistically significant.THC caused a lowering of cAMP and cGMP levels throughout the 4-h experimental treatment. The suppression of cAMP and cGMP levels altered the cyclic nucleotide pattern of the cell cycle. The cAMP pattern was changed particularly in the G2 period preceding the first synchronous division, and immediately after division during the free running cell cycle. THC treatment caused division delays of approximately 8–15 min in the onset of the first and second synchronous division. However, the duration of the free running cell cycle (110–120 min) was unchanged. The suppression of cyclic nucleotide levels resulting from THC treatment is discussed in relation to delays in the division schedule.Nous avons déterminé le taux des nucléotides cycliques chez Tetrahymena se divisant de façon synchrone et nous avons étudié l'effet du Δ9-tétrahydrocannabinol (THC) sur le taux de ces nucléotides cycliques. Dans les cellules non traitées, se divisant de façon synchrone, il n'existe aucune variation statistiquement significative dans les teneurs du cAMP et du cGMP durant la période G2 précédant la première division. Durant le cycle cellulaire sans division (l'intervalle de temps entre la première et la seconde division synchrone), la teneur du cAMP augmente de deux fois, une augmentation statistiquement significative; cependant, la variation du taux du cGMP n'est pas statistiquement significative.