In Experiment 1, we examined the Selleckchem Torin 1 effects of unilateral lesions of CeA and/or VTA on rats’ acquisition of conditioned responses to visual cues paired with food. Contrary to the results of previous studies that examined interactions
of CeA with either SNc or DLS, rats with contralateral disconnection lesions of CeA and VTA were unimpaired in their acquisition of cue-directed responses. By contrast, rats with lesions of both structures in the same hemisphere failed to learn cue-directed responses, but were normal in their acquisition of conditioned responses directed to the food cup. In Experiment 2, we attempted to characterize the influence of VTA on CeA by examining FOS induction in CeA by a visual cue for food in rats with unilateral lesions of VTA. The results suggested an excitatory influence of VTA on CeA in the presence of food cues. Implications of these results for brain circuits involved in learned orienting and incentive motivation are discussed. “
“Synapsins are abundant synaptic vesicle (SV)-associated proteins thought
to mediate synaptic vesicle mobility and clustering at most synapses. We used synapsin triple knock-out (TKO) mice to examine the morphological and functional consequences Ganetespib of deleting all synapsin isoforms at the calyx of Held, a giant glutamatergic synapse located in the auditory brain stem. Quantitative three-dimensional (3D) immunohistochemistry of entire calyces showed lower amounts of the synaptic vesicle protein vGluT1 while the level of the active zone marker bassoon was unchanged in TKO terminals. Examination of brain lysates by ELISA revealed a strong reduction in abundance of several synaptic vesicle proteins, while proteins of the active zone cytomatrix or postsynaptic density were unaffected. Serial section scanning electron microscopy of large 3D-reconstructed segments confirmed a decrease in the number of SVs to approximately 50% in TKO calyces. Short-term depression tested at stimulus
frequencies ranging from 10 to 300 Hz was accelerated only at frequencies above 100 Hz and the time course of recovery from depression was slowed in calyces lacking synapsins. Histone demethylase These results reveal that in wild-type synapses, the synapsin-dependent reserve pool contributes to the replenishment of the readily releasable pool (RRP), although accounting only for a small fraction of the SVs that enter the RRP. In conclusion, our results suggest that synapsins may be required for normal synaptic vesicle biogenesis, trafficking and immobilization of synaptic vesicles, yet they are not essential for sustained high-frequency synaptic transmission at the calyx terminal. “
“Department of Neuroscience, Physiology and Pharmacology, University College, London, UK The K+-Cl− cotransporter type 2 is the major Cl− extrusion mechanism in most adult neurons.