ABSTRACT
Synaptotagmin 7 (Syt7) is a high-affinity calcium sensor that is implicated in multiple aspects of synaptic transmission. Here, we study the influence of Syt7 on the climbing fiber (CF) to Purkinje cell (PC) synapse. We find that small facilitation and prominent calcium-dependent recovery from depression at this synapse do not rely on Syt7 and that Syt7 is not normally present in CFs. We expressed Syt7 in CFs to assess the consequences of introducing Syt7 to a synapse that normally lacks Syt7. Syt7 expression does not promote asynchronous release or accelerate recovery from depression. Syt7 decreases the excitatory postsynaptic current (EPSC) magnitude, consistent with a decrease in the initial probability of release (PR). Syt7 also increases synaptic facilitation to such a large extent that it could not arise solely as an indirect consequence of decreased PR. Thus, the primary consequence of Syt7 expression in CFs, which normally lack Syt7, is to promote synaptic facilitation.
Subject(s)
Synapses/metabolism , Synaptotagmins/metabolism , Animals , Calcium/metabolism , Calcium/pharmacology , Depression/metabolism , Depression/pathology , Disease Models, Animal , Excitatory Postsynaptic Potentials/drug effects , Female , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Neuronal Plasticity , Neurons/metabolism , Purkinje Cells/cytology , Purkinje Cells/metabolism , Synaptic Transmission , Synaptotagmins/deficiency , Synaptotagmins/geneticsABSTRACT
Immediate hypersensitivity reactions to systemic steroids are reported rarely in the literature. The authors present a case of Behçet's disease-associated panuveitis in a patient with skin test confirmed immunoglobulin E-mediated allergy to methylprednisolone and reported allergic reaction to prednisone. The patient tolerated prednisolone eyedrops for his anterior segment disease, as well as oral prednisolone for systemic therapy. This case demonstrates a challenge to conventional treatment, as it involves a hypersensitivity that is rarely reported. It also highlights class differences in corticosteroids with regard to immune reactivity. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:447-449.].
Subject(s)
Behcet Syndrome , Hypersensitivity , Behcet Syndrome/complications , Behcet Syndrome/diagnosis , Behcet Syndrome/drug therapy , Humans , Prednisolone , SteroidsABSTRACT
Although the cerebellum is traditionally associated with balance and motor function, it also plays wider roles in affective and cognitive behaviors. Evidence suggests that the cerebellar vermis may regulate aggressive behavior, though the cerebellar circuits and patterns of activity that influence aggression remain unclear. We used optogenetic methods to bidirectionally modulate the activity of spatially-delineated cerebellar Purkinje cells to evaluate the impact on aggression in mice. Increasing Purkinje cell activity in the vermis significantly reduced the frequency of attacks in a resident-intruder assay. Reduced aggression was not a consequence of impaired motor function, because optogenetic stimulation did not alter motor performance. In complementary experiments, optogenetic inhibition of Purkinje cells in the vermis increased the frequency of attacks. These results suggest Purkinje cell activity in the cerebellar vermis regulates aggression, and further support the importance of the cerebellum in driving affective behaviors that could contribute to neurological disorders.
