Diazepam modulates the period of locomotor rhythm in mice (Mus booduga) and attenuates light-induced phase advances

Chronic Ethanol Intake Alters Circadian Period‐Responses to Brief Light Pulses in Rats

“…Thus, although several ethanol-sensitive neurotransmitter and receptor systems are known to play key roles in circadian pacemaker regulation (Rosenwasser, 2001), the hypothesis that alcohol intake affects the circadian pacemaker via its action on these neural systems remains largely untested. This surprising lack of evidence stands in marked contrast to the extensive available data indicating that the central circadian pacemaker is indeed sensitive to several other classes of mood-altering psychoactive drugs, including antidepressants (Wollnik, 1992;Klemfuss and Kripke, 1994;Duncan et al, 1998), benzodiazepines (Turek and Losee-Olson, 1986;Subramanian and Subbaraj, 1996), and putative depressogenic agents (Rosenwasser, 1996).…”

“…Surprisingly, both lengthening and shortening of free-running period have been observed, even for a given agent, and these effects appear to be modulated by a variety of factors, including both lighting conditions and individual differences in baseline period (Rosenwasser, 1996;Rosenwasser et al, 2005). In contrast, the reported effects of mood-altering drugs on the response of the circadian pacemaker to light pulses have been more consistent: despite their diverse pharmacological effects, clorgyline, lithium (Duncan et al, 1998), diazepam (Subramanian and Subbaraj, 1996), clonidine (Dwyer and Rosenwasser, 2000), and ethanol (present data) all appear to blunt the pacemaker's responsiveness to light. In addition, two laboratories have recently reported blunting of the circadian pacemaker's response to photic stimuli in adulthood following perinatal ethanol treatments (Sei et al, 2003;Farnell et al, 2004).…”

“…For example, alterations in free-running circadian period have been described during chronic administration of several different classes of antidepressants (Wollnik, 1992;Klemfuss and Kripke, 1994;Rosenwasser and Wirz-Justice, 1997;Duncan et al, 1998), the anxiolytic benzodiazepine, diazepam (Subramanian and Subbaraj, 1996), the putative depressogenic agent, clonidine (Rosenwasser, 1996), and ethanol (Dwyer and Rosenwasser, 1998;Rosenwasser et al, 2005). Surprisingly, both lengthening and shortening of free-running period have been observed, even for a given agent, and these effects appear to be modulated by a variety of factors, including both lighting conditions and individual differences in baseline period (Rosenwasser, 1996;Rosenwasser et al, 2005).…”

“…On the other hand, emerging evidence from animal experiments suggests that both adult (Mistlberger and Nadeau, 1992;Dwyer and Rosenwasser, 1998;Rosenwasser et al, 2005) and perinatal (Earnest et al, 2001) ethanol treatment can modify the free-running circadian period, a fundamental parameter of the circadian pacemaker. Indeed, chronic ethanol treatment can evoke both lengthening and shortening of free-running circadian period (Rosenwasser et al, 2005), similar to the period-altering effects of chronic treatment with other mood-altering drugs (Rosenwasser, 1996;Subramanian and Subbaraj, 1996;Rosenwasser and Wirz-Justice, 1997).…”

“…In addition to their effects on free-running period, these same drug treatments also modify the response of the circadian pacemaker to light, including the acute phase-shifting effects of brief light pulses (Subramanian and Subbaraj, 1996;Duncan et al, 1998;Dwyer and Rosenwasser, 2000), the period-lengthening effect of constant light (Dwyer and Rosenwasser, 2000), and the phase of steady-state entrainment under daily light-dark cycles (Tamarkin et al, 1983). Thus, our study was designed to more completely characterize the chronobiological effects of ethanol by examining the effects of chronic ethanol treatment on the response of the circadian pacemaker to brief light pulses in rats.…”