Centre for Neuroscience - Research Publications
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ItemDifferential effects of early environmental enrichment on emotionality related behaviours in Huntington's disease transgenic mice(WILEY, 2013-01)Psychiatric disorders such as depression and anxiety are reported in patients with Huntington's disease (HD). Recent studies suggest beneficial effects of environmental enrichment (EE) on HD progression possibly through the serotonergic system. We investigated the potential effectiveness of EE in correcting the affective-like phenotype of female R6/1 HD mice. In addition to a behavioural battery of tests assessing depression and anxiety-related endophenotypes, we recorded physiological measures, including body temperature regulation and defecation rate as indices of stress reactivity. Finally, following identification of changes in serotonin (5-HT) receptor gene expression we measured the function of 5-HT(1A) auto- and hetero-receptors. We found that 8-week-old female HD mice exhibited higher immobility time in the forced swimming test and a decreased preference for saccharin solution. EE did not correct those depressive-like behaviours but reduced anxiety-related measures in unconditioned approach/avoidance conflict situations. Defecation rate in a large open field and change in temperature during exposure to the tail suspension test were both enhanced in HD compared to wild-type animals. Despite the enhanced hypothermic response to the 5-HT(1A) receptor agonist 8-OH-DPAT exhibited by HD mice, we found a reduction in 5-HT(1A) receptor-mediated stimulation of [(35)S]GTP-γ-S binding in the dorsal raphe nucleus and the hippocampus of HD animals. EE did not change 5-HT(1A) receptor function. Our data suggest that early EE has beneficial effects on the anxiety-like, but not on depression-like, behaviours in HD. This is the first evidence that these affective endophenotypes can be dissociated via this form of environmental stimulation. As 5-HT(1A) receptor dysfunction was not affected by EE, this receptor is unlikely to underlie the anxiety-related phenotype of HD. However, the specific regulatory role of the 5-HT(1A) autoreceptor in mediating depressive-like behaviour in HD remains to be elucidated. Interestingly, by comparing in vivo and in vitro results, our findings suggest that 8-OH-DPAT-induced hypothermia could be mediated by other targets besides the 5-HT(1A) autoreceptor, including hippocampal 5-HT(7) receptors.
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ItemGENDER AND BEING BORN OVERSEAS INFLUENCES THE AMOUNT OF ACUTE STROKE THERAPY(FOUNDATION REHABILITATION INFORMATION, 2013-02)OBJECTIVE: To identify patient factors that influence the amount, frequency and intensity of physical and occupational therapy received by patients each weekday within 14 days of stroke. DESIGN: Exploration of data from studies conducted to monitor activity and therapy. PARTICIPANTS: Stroke patients receiving active treatment (not for palliative care). Physiotherapists and occupational therapists. RESULTS: Therapy data for 274 patients from 7 hospitals were included. Patients received a median of 40.0 min of therapy (physiotherapy plus occupational therapy) per weekday. Multivariable regression found that women had 22% less total therapy per weekday (factor change 0.78, 95% confidence interval (CI): 0.66-0.9, p = 0.001) and a decreased likelihood of receiving two or more sessions of therapy per weekday. Those born overseas had 23% less high intensity therapy per weekday (Factor change 0.77, 95% CI: 0.71-0.84, p < 0.001). Those with more severe stroke had a greater likelihood of receiving two or more sessions of therapy per weekday (OR = 1.05, 95% CI: 1.02-1.09, p = 0.006) but increasing severity increased the odds of receiving no high intensity therapy by 7% (factor change 1.07, 95% CI: 1.02-1.11, p = 0.002). Age did not exhibit a significant association. CONCLUSION: There is some evidence that patient factors may influence the amount of therapy provided. Physiotherapists and occupational therapists should be aware of potential biases associated with therapy provision.
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