ABSTRACT
The use of gabapentin in treating dogs with behavioral disorders is not well described. To characterize behavioral effects of gabapentin, this study surveyed 50 owners whose dogs were prescribed gabapentin at a veterinary behavior-focused practice over a five-year period. Most owners (72%) reported that gabapentin was moderately or very effective at improving their dog's behavior. The majority of owners reported at least one side effect (70%), with sedation being the most common. Sedation was more likely to be seen at doses higher than 30 mg/kg. Specific dose ranges (mg/kg) did not correlate with any other reports of side effects nor effectiveness. Dogs with a diagnosis of conflict-related aggression were more likely to have owners report that gabapentin was effective at improving behavior compared to dogs with other behavioral diagnoses (p = 0.04), while dogs diagnosed with aggression secondary to high arousal were less likely to have owners report that gabapentin was effective (p = 0.01). Overall, reports of effect varied widely and, with the exception of sedation, did not correlate with specific mg/kg dose ranges. Results suggest that some dogs may be more sensitive or resistant to adverse and/or therapeutic effects than others and multiple dosage trials may be needed before finding the best fit.
ABSTRACT
Sex hormones are well known to modulate circadian timekeeping as well as the behavioral and physiological responses to circadian disruption. Gonadectomy, reducing the amount of circulating gonadal hormones, in males and females produces alterations to the free-running rhythm and the responses to light exposure by the central oscillator of the suprachiasmatic nucleus (SCN). In this study, we tested whether estradiol plays a role in regulating the circadian responses to acute (light pulses) and chronic light exposure (constant light [LL] vs standard light:dark [LD] cycle) in female C57BL6/NJ mice. Mice were either ovariectomized or given sham surgery and given a placebo (P) or estradiol (E) pellet for hormone replacement so that there were 6 groups: (1) LD/Sham, (2) LL/Sham, (3) LD/OVX + P, (4) LL/OVX + P, (5) LD/OVX + E, and (6) LL/OVX + E. After 65 days of light cycle exposure, blood and SCNs were removed and serum estradiol plus SCN estradiol receptor alpha (ERα) and estradiol receptor beta (ERß) were measured via ELISA. The OVX + P mice exhibited shorter circadian periods and were more likely to become arrhythmic in LL compared with mice with intact estradiol (sham or E replacement mice). The OVX + P mice exhibited reduced circadian robustness (power) and reduced circadian locomotor activity in both LD and LL compared with sham controls or OVX + E mice. The OVX + P mice also exhibited later activity onsets in LD and attenuated phase delays, but not advances, when given a 15-min light pulse compared with estradiol intact mice. LL led to reductions in ERß, but not ERα, regardless of the surgery type. These results indicate that estradiol can modulate the effects of light on the circadian timing system and that estradiol can enhance responses to light exposure and provide protection against a loss of circadian robustness.
