The effect of 5‐HT_1A receptor agonists on the entopeduncular nucleus is modified in 6‐hydroxydopamine‐lesioned rats

Abstract

Author contributions L.U. and C.M. conceived the study, designed the experiments, and drafted the final version of the manuscript. S.V.S. performed all the experiments, carried out data quantification and analysis, prepared the figures, and contributed to the first draft. A. A. and C. M. collaborated in the optogenetic experiments. C.R. and H.B. contributed to the immunostaining experiment design. C.M. revised the data analysis. S.V.S., C.M., J.V.L., A.S., and L.U. interpreted the results. All authors reviewed and edited the manuscript.

Different Alterations of Agonist and Antagonist Binding to 5-HT1A Receptor in a Rat Model of Parkinson’s Disease and Levodopa-Induced Dyskinesia: A MicroPET Study

“…Alternatively, 5-HT1AR coupling state might be altered in this region, which is supported by very recent findings in 6-OHDA lesioned rats showing that 5-HT1A agonists effects are decreased in the entopeduncular nucleus (which is analogous to the internal part of the globus pallidus) compared to control rats [79]. In the contralateral side, [ 18 F]F13640 uptake was increased in limbic areas or limbic-related areas such as the insula, the entorhinal cortex, and the amygdala and the ventral hippocampus.…”

Motor cortico-nigral and cortico-entopeduncular information transmission and its modulation by buspirone in control and after dopaminergic denervation

“…With all, studies evaluating 5-HT 1A receptors in different regions report variable results. In hemiparkinsonian rats, we have observed a slight but significant reduction in 5-HT 1A receptor immunoreactivity in the striatum and GPe after DA loss ( Vegas-Suárez et al, 2021 ), in line with a micro-PET study ( Vidal et al, 2021 ). The use of other techniques such as autoradiography and in situ hybridization for 5-HT 1A studies failed to support those results in the striatum ( Radja et al, 1993 ; Numan et al, 1995 ).…”

“…Three weeks after the 6-OHDA lesion, forelimb asymmetry was evaluated ( Vegas-Suárez et al, 2020 ; Vegas-Suárez et al, 2021 ). Each rat was left in a 20-cm diameter methacrylate cylinder until reaching a total of 20 touches with any of both forelimbs on the walls during exploratory behavior or a maximum of 5-min exploration time.…”

“…At least 4 weeks after the lesion, electrophysiological procedures were performed as previously described ( Antonazzo et al, 2019 ; Vegas-Suárez et al, 2020 ; Vegas-Suárez et al, 2021 ). Animals were anesthetized with urethane (1.2 g/kg, i.p.…”

“…The 5-HT neurons from the dorsal raphe nucleus (DRN) innervate almost all brain areas including the BG nuclei ( Huang et al, 2019 ). DA loss is also associated with alterations in 5-HT neurotransmission coming from the raphe nuclei to the BG nuclei ( Di Matteo et al, 2008 ) causing, among others, changes in the response mediated by 5-HT 1A receptor activation on cortical pyramidal neurons ( Wang et al, 2009 ), STN ( Sagarduy et al, 2016 ), SNr, and EP ( Vegas-Suárez et al, 2020 ; Vegas-Suárez et al, 2021 ). The modulatory action of 5-HT 1A receptors on cortico-BG transmission might be changed by DA loss, as they are expressed throughout the whole BG ( Lanfumey and Hamon, 2000 ).…”