Effects of Diazepam on Gene Expression and Link to Physiological Effects in Different Life Stages in Zebrafish Danio rerio

Abstract

We applied zebrafish whole genome microarrays to identify molecular effects of diazepam, a neuropharmaceutical encountered in wastewater-contaminated environments, and to elucidate its neurotoxic mode of action. Behavioral studies were performed to analyze for correlations between altered gene expression with effects on the organism level. Male zebrafish and zebrafish eleuthero-embryos were exposed for 14 d or up to 3 d after hatching, respectively, to nominal levels of 273 ng/L and 273 μg/L (determined water concentrations in the adult experiment 235 ng/L and 291 μg/L). Among the 51 and 103 altered transcripts at both concentrations, respectively, the expression of genes involved in the circadian rhythm in adult zebrafish and eleuthero-embryos were of particular significance, as revealed both by microarrays and quantitative PCR. The swimming behavior of eleuthero-embryos was significantly altered at 273 μg/L. The study leads to the conclusion that diazepam-induced alterations of genes involved in circadian rhythm are paralleled by effects in neurobehavior at high, but not at low diazepam concentrations that may occur in polluted environments.

Progestins as endocrine disrupters in aquatic ecosystems: Concentrations, effects and risk assessment

“…4 summarizes the expressional changes in key genes of the circadian rhythm found to be altered by P4 and progestins in the brain of female zebrafish. The pattern of transcriptional changes induced by these progestins resembled those found in zebrafish exposed to the neuropharmaceutical diazepam (valium) (Oggier et al, 2010).…”

Diazepam and Fluoxetine Decrease the Stress Response in Zebrafish

“…The environmental concentrations of these drugs range from 0.04 to 0.88 µg/L for diazepam [4]–[6] and 0.012 to 1 µg/L for fluoxetine [4], [7]–[10]. Benzodiazepines and SSRIs exert anxiolytic effects and can interfere with neuroendocrine stress axis activity [11]–[14]. Although these drugs have been detected in an extensive variety of environments, there is little information regarding the effects of these compounds in living organisms [15].…”

Chronopharmacology of Anti-Convulsive Therapy

“…Diazepam was noted to alter the phase of the circadian clock by increasing or decreasing the expression of clock genes in adult and embryonic zebrafish [83]. This finding may possibly extend to other benzodiazepines.…”