Enhanced muscimol-induced behavioral responses after 6-OHDA lesions: relevance to susceptibility for self-mutilation behavior in neonatally lesioned rats

Adult rats lesioned with 6-hydroxydopamine (6-OHDA), either as neonates or as adults, demonstrated increased turning, compared to unlesioned controls, when muscimol was unilaterally microinjected into the substantia nigra reticulata (SNR). At the higher doses of muscimol, the lesioned rats were so intensely lateralized that circling was impeded. These data suggest a functional supersensitivity of receptors associated with GABA function in the SNR of 6-OHDA-lesioned rats. When 30 ng muscimol was administered bilaterally into the SNR, self-mutilation behavior (SMB) was observed in 2/11 of the control unlesioned rats, in 0/8 adult 6-OHDA-lesioned rats, and in 11/11 of the neonatally-lesioned rats tested. The ability of muscimol to produce SMB in the rats lesioned as neonates was dose related. Behavioral observations indicated that behaviors associated with SMB (self-biting and taffy pulling) were present in neonatal, but not adult lesioned rats. Behavioral responses to dopamine agonist administration were also different between rats lesioned as neonates and those lesioned as adults with 6-OHDA. These data support the view that lesions of dopaminergic neurons cause an increased functional responsiveness of receptors acted upon by muscimol in the SNR, and that the increased susceptibility for SMB in neonatally lesioned rats is determined by neurons distal to the GABA receptor complex in the SNR

A systematic review on integration mechanisms in human and animal health surveillance systems with a view to addressing global health security threats

Lymphatic filariasis and onchocerciasis are neglected tropical diseases (NTDs) targeted for elimination by mass (antifilarial) drug administration. These drugs are predominantly active against the microfilarial progeny of adult worms. New drugs or combinations are needed to improve patient therapy and to enhance the effectiveness of interventions in persistent hotspots of transmission. Several therapies and regimens are currently in (pre-)clinical testing. Clinical trial simulators (CTSs) project patient outcomes to inform the design of clinical trials but have not been widely applied to NTDs, where their resource-saving payoffs could be highly beneficial. We demonstrate the utility of CTSs using our individual-based onchocerciasis transmission model (EPIONCHO-IBM) that projects trial outcomes of a hypothetical macrofilaricidal drug. We identify key design decisions that influence the power of clinical trials, including participant eligibility criteria and post-treatment follow-up times for measuring infection indicators. We discuss how CTSs help to inform target product profiles