Lack of sex differences in anxiety behaviors during precipitated benzodiazepine withdrawal in rats

Progesterone withdrawal effects in the open field test can be predicted by elevated plus maze performance

Allopregnanolone (3alpha-hydroxy-5alpha-pregnane-20-one) is a ring-A-reduced metabolite of progesterone, which is naturally produced during the luteal phase of the menstrual cycle, during pregnancy and by stressful events. The steroid hormone inhibits neural functions through increased chloride ion flux through the GABA(A) receptor. The effects and subsequent withdrawal symptoms are similar to those caused by alcohol, benzodiazepines and barbiturates. This study examined the withdrawal effects of progesterone with regards to the influence of individual baseline exploration and risk taking. Rats were tested on the elevated plus maze (EPM) before hormonal treatment, in order to evaluate differences in risk taking and exploration of open and elevated areas. Treatment consisted of ten consecutive once a day progesterone or vehicle s.c. injections. On the last day of treatment, estradiol was injected in addition to progesterone, followed by a 24-h withdrawal before testing in the open field test (OF). Progesterone-treated rats showed a withdrawal effect of open area avoidance in the OF. The vehicle-treated control rats showed strong correlations between the EPM and OF parameters. This relationship was not found for the progesterone group at withdrawal. Rats with greater numbers of open arm entrance in the EPM pretest showed an increased sensitivity to progesterone withdrawal (PWD) compared to rats with low exploration and risk taking. The results indicate that the effects of PWD relate to individual exploration and risk taking. Furthermore, the possible analogy of PWD and PMS/PMDD in relation to individual traits is discussed.

Sex-related elevation in cortisol during chronic treatment with alprazolam associated with enhanced cognitive performance

OBJECTIVE

There is evidence of more widespread use and abuse of benzodiazepines (BZPs) among elderly women. However, factors underlying this observation are poorly understood but could be related to more intense withdrawal reactions, which are a major risk factor for continued BZP use. We previously reported elevations in interdose morning plasma cortisol levels in healthy elderly individuals after chronic treatment with alprazolam, possibly consistent with increased hypothalamic-pituitary-adrenal (HPA) axis activity and drug withdrawal. In this study, we examined sex-related differences in this population.

METHOD

Twenty-five cognitively intact healthy elderly (13 women and 12 men) participated in a parallel, double-blind, placebo-controlled study that included a group that received acute and chronic (3 weeks) treatment with alprazolam (0.5 mg b.i.d.).

RESULTS

Elderly women, but not men, experienced significant elevations in interdose morning plasma cortisol levels over 3 weeks of chronic treatment with alprazolam (0.5 mg b.i.d.) compared to placebo. In addition, higher morning plasma cortisol levels were significantly associated with better cognitive performance but not with higher plasma drug levels or greater degree of tolerance development to an acute alprazolam challenge.

CONCLUSION

Elderly females experienced a greater interdose activation of the HPA axis during treatment with therapeutic doses of alprazolam than men, which could be related to drug withdrawal.

Hippocampal 3α,5α-THP may alter depressive behavior of pregnant and lactating rats

The 5alpha-reduced metabolite of progesterone (P), 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), may mediate progestins' effects to reduce depressive behavior of female rats in part through actions in the hippocampus. To investigate, forced swim test behavior and plasma and hippocampal progestin levels were assessed in groups of rats expected to differ in their 3alpha,5alpha-THP levels due to endogenous differences (pregnant and postpartum), administration of a 5alpha-reductase inhibitor (finasteride; 50 mg/kg sc), and/or gestational stress [prenatal stress (PNS)], an animal model of depression. Pregnant rats had higher plasma and hippocampal 3alpha,5alpha-THP levels and less depressive behavior (decreased immobility, increased struggling and swimming) in the forced swim test than did postpartum rats. Finasteride, compared to vehicle-administration, reduced plasma and hippocampal 3alpha,5alpha-THP levels and increased depressive behavior (increased immobility, decreased struggling and swimming). PNS was associated with lower hippocampal, but not plasma, 3alpha,5alpha-THP levels and increased swimming compared to that observed in control rats. Together, these data suggest that 3alpha,5alpha-THP in the hippocampus may mediate antidepressive behavior of female rats.