The distribution of neuronal primary cilia immunoreactive to melanin-concentrating hormone receptor 1 (MCHR1) in the murine prosencephalon

Abstract

Melanin-concentrating hormone (MCH) is a ubiquitous vertebrate neuropeptide predominantly synthesized by neurons of the diencephalon that can act through two G protein-coupled receptors, called MCHR1 and MCHR2. The expression of Mchr1 has been investigated in both rats and mice, but its synthesis remains poorly described. After identifying an antibody that detects MCHR1 with high specificity, we employed immunohistochemistry to map the distribution of MCHR1 in the CNS of rats and mice. Multiple neurochemical markers were also employed to characterize some of the neuronal populations that synthesize MCHR1. Our results show that MCHR1 is abundantly found in a sensory subcellular structure called the neuronal primary cilium, which has been associated with the detection of free neurochemical agents released to act through volume transmission. Ciliary MCHR1 was found in a wide range of areas, including the olfactory bulb, cortical mantle, striatum, hippocampal formation, amygdala, midline thalamic nuclei, periventricular hypothalamic nuclei, and midbrain areas. No differences were observed between male and female mice, and rats and mice diverged in two key areas: the caudate-putamen nucleus and the subgranular zone of the dentate gyrus. Ciliary MCHR1 was found in close association to several neurochemical markers, including tyrosine hydroxylase, calretinin, kisspeptin, estrogen receptor, oxytocin, vasopressin, and corticotropinreleasing factor. Given the role of neuronal primary cilia in sensing free neurochemical messengers in the extracellular fluid, the widespread distribution of ciliary MCHR1, and the diverse neurochemical populations who synthesize MCHR1, our data indicates that volume transmission may play a prominent role in the normal function of the MCH system. Diniz et al, 2019 Ciliary MCHR1 in murines 3

Power and coherence in the EEG of the rat: impact of behavioral states, cortical area, lateralization and light/dark phases

“…Because of this, for the day/night and laterality analyses we also performed a second evaluation by means of a cluster-based permutation test, consisting of comparing empirical clusters of frequencies against a randomized distribution, thus allowing the frequency bands to be delimited in a statistical approach without the need of a previous convention (Gonzalez et al, 2020a). Statistical evaluation of the absolute spectral power in function of cortical regions, behavioral state, and interaction between both factors.…”

“…During REM sleep, the relative weight of the theta band is highlighted with the analysis of the relative power (Figure 4). The main origin of theta rhythm is in the hippocampus; this hippocampal theta rhythm modulates cortical neuronal activity (Cavelli et al, 2018;Gonzalez et al, 2020b;Sirota et al, 2008;Winson, 1974). A prominent peak in theta and relatively large power in gamma and HFO (larger than during NREM sleep) characterize REM sleep (Cavelli et al, 2018).…”