Corticotrophin-Releasing Factor Modulates the Facial Stimulation-Evoked Molecular Layer Interneuron-Purkinje Cell Synaptic Transmission in vivo in Mice

Abstract

Corticotropin-releasing factor (CRF) is an important neuromodulator in central nervous system that modulates neuronal activity via its receptors during stress responses. In cerebellar cortex, CRF modulates the simple spike (SS) firing activity of Purkinje cells (PCs) has been previously demonstrated, whereas the effect of CRF on the molecular layer interneuron (MLI)–PC synaptic transmission is still unknown. In this study, we examined the effect of CRF on the facial stimulation–evoked cerebellar cortical MLI-PC synaptic transmission in urethane-anesthetized mice by in vivo cell-attached recording, neurobiotin juxtacellular labeling, immunohistochemistry techniques, and pharmacological method. Cell-attached recordings from cerebellar PCs showed that air-puff stimulation of ipsilateral whisker pad evoked a sequence of tiny parallel fiber volley (N1) followed by MLI-PC synaptic transmission (P1). Microapplication of CRF in cerebellar cortical molecular layer induced increases in amplitude of P1 and pause of SS firing. The CRF decreases in amplitude of P1 waveform were in a dose-dependent manner with the EC50 of 241 nM. The effects of CRF on amplitude of P1 and pause of SS firing were abolished by either a non-selective CRF receptor antagonist, α-helical CRF-(9-14), or a selective CRF-R1 antagonist, BMS-763534 (BMS, 200 nM), but were not prevented by a selective CRF-R2 antagonist, antisauvagine-30 (200 nM). Notably, application CRF not only induced a significant increase in spontaneous spike firing rate, but also produced a significant increase in the number of the facial stimulation–evoked action potential in MLIs. The effect of CRF on the activity of MLIs was blocked by the selective CRF-R1 antagonist, and the MLIs expressed the CRF-R1 imunoreactivity. These results indicate that CRF increases excitability of MLIs via CRF-R1, resulting in an enhancement of the facial stimulation–evoked MLI-PC synaptic transmission in vivo in mice.

Facial Stimulation Induces Long-Term Potentiation of Mossy Fiber-Granule Cell Synaptic Transmission via GluN2A-Containing N-Methyl-D-Aspartate Receptor/Nitric Oxide Cascade in the Mouse Cerebellum

“…Microscope slides with slices were then washed 3 times in PBS covered with a coverslip and sealed with nail polish. Fluorescence images were acquired by confocal laser scanning microscope (Nikon C2, Tokyo, Japan) ( Mi et al, 2018 ; Wu et al, 2020 ). A large region image including Crus II was obtained on Nikon C2 laser confocal system with 10 × objective.…”

Opposing Actions of CRF-R1 and CB1 Receptor on Facial Stimulation-Induced MLI-PC Plasticity in Mouse Cerebellar Cortex

“…Immunohistochemical study has revealed that both CRF-R1 and CRF-R2 were expressed in adult rat cerebellum (Swinny et al, 2003). CRF release from CRFergic mossy ber terminals in granular layer and molecular layer could regulate mossy ber-granule cell, parallel ber-PC and parallel ber-MLIs synaptic transmission and long-term plasticity Wang et al, 2018;Wu et al, 2020). We recently found that CRF increases excitability of MLIs, resulting in a signi cant enhancement of the facial stimulation-evoked MLI-PC synaptic transmission via activation of CRF-R1 in vivo in mice, suggesting that CRF modulates MLI-PC synaptic transmission and long-term plasticity and play a critical role in motor learning in living animals (Wu et al, 2020).…”

“…CRF release from CRFergic mossy ber terminals in granular layer and molecular layer could regulate mossy ber-granule cell, parallel ber-PC and parallel ber-MLIs synaptic transmission and long-term plasticity Wang et al, 2018;Wu et al, 2020). We recently found that CRF increases excitability of MLIs, resulting in a signi cant enhancement of the facial stimulation-evoked MLI-PC synaptic transmission via activation of CRF-R1 in vivo in mice, suggesting that CRF modulates MLI-PC synaptic transmission and long-term plasticity and play a critical role in motor learning in living animals (Wu et al, 2020). Interestingly, our present results showed that CRF failed to prevent the facial stimulation-induced MLI-PC LTD in mouse cerebellar cortex in the absence of CRF-R1 activity, suggesting that activation of CRF-R1 impaired the expression of MLI-PC LTD.…”

“…Activation of CRF-R1 play an important role in the responses to stressful challenges, and act as critical roles in regulating particular forms of cerebellar learning both at the cellular and behavioral levels, but without an effect on baseline motor skills (Ezra-Nevo et al, 2018b; Wang et al, 2017). We recently found that activation of CRF-R1 increases excitability of MLIs and enhances the facial stimulation-evoked MLI-PC synaptic transmission in vivo in mice, suggesting that CRF modulates MLI-PC synaptic transmission and long-term plasticity (Wu et al, 2020).…”

Opposing actions of CRF-R1 and CB1 receptor on facial stimulation-induced MLI-PC plasticity in mouse cerebellar cortex

“…Both CRF-R1 and CRF-R2 are expressed in the cerebellum of adult rodents [ 7 – 9 ]. CRF-R1 is found in all lobules of the cerebellar cortex, including Purkinje cells (PCs), molecular layer interneurons (MLIs), Golgi cells and granule cells [ 10 – 12 ]. In contrast, CRF-R2 has been found in the cerebellar cortical molecular layer, such as in parallel fibers and their terminals [ 11 , 13 ].…”