Temporal variations in presynaptic release probability in the lateral habenula

Abstract

Rhythmicity plays an important role in a number of biological systems. The habenular complex is reported to contain an intrinsic molecular clock and to show rhythmic expression of circadian clock genes and proteins including per2/PER2. In this study, we observed that there is a temporal rhythmicity in the presynaptic efficacy of the lateral habenula (LHb) neurons. We collected a substantial number of recordings at different time points of the day during the light phase. The frequency and amplitude of spontaneous excitatory transmission were increased in the afternoon compared to recordings performed in the morning. In addition, the paired-pulse ratio and the success rate of minimal stimulation were also significantly different depending on the time of the recording. We did not see any significant differences in recordings obtained from pyramidal neurons of the hippocampus in the same brain slices. Taken together, our data indicates that the LHb exhibits intrinsic temporal oscillation in basal neurotransmission and in presynaptic release probability. Given the rapidly growing interest on the function of the LHb, more careful examination of synaptic transmission in the LHb is thus required.

Systemic Cellular Activation Mapping of an Extinction-Impaired Animal Model

“…Ventral to the hippocampus lies the PVT and LHb. The PVT has recently been proposed to be involved in long-term fear memory storage (Arruda-Carvalho and Clem, 2015 ; Do-Monte et al, 2015b ; Penzo et al, 2015 ), and the LHb is related to depression-like behaviors (Matsumoto and Hikosaka, 2007 , 2009 ; Li et al, 2011 ; Park et al, 2017a , b , c ). 129S1 mice exhibited higher activity in the PVT after contextual fear extinction.…”

Circadian regulation of membrane physiology in neural oscillators throughout the brain

“…Furthermore, whole‐cell recordings in the LHb reveal that the time of day changes in LHb firing frequency—which is usually lower in early day compared to the late day—are lost in Cry1/2 ‐deficient mice (Sakhi, Wegner, et al., ). It is important to note that temporal differences in firing frequency (Zhao & Rusak, ) may be due to presynaptic input rather than intrinsic LHb activity because Park, Cheon, Kim, and Chung () reported an increase in mini‐excitatory postsynaptic current (mEPSC) frequency and paired‐pulse ratio (when stimulating in stria medullaris) in afternoon compared to morning.…”

Review of the cytology and connections of the lateral habenula, an avatar of adaptive behaving

“…Further research into the mechanisms underlying co-released glutamate and GABA in LHb may provide novel insights into such motivational states as well as disorders involving the LHb. Some recent observations include that excitatory and inhibitory LHb synapses exhibit differential plasticity modulated by distinct mechanisms (Valentinova and Mameli, 2016), that glutamate and GABA release are differentially regulated by mu opioid receptor activation (Margolis and Fields, 2016), that GABA receptors are specifically internalized in response to stress (Lecca et al, 2016), that AMPA receptors are enhanced at excitatory synapses following cocaine exposure (Marteau and Mamelli, 2012; Meye et al, 2015), and that LHb neurotransmission undergoes circadian modulations (Park et al, 2017). …”