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The theta‐related firing activity of parvalbumin‐positive neurons in the medial septum‐diagonal band of broca complex and their response to 5‐HT 1A Receptor stimulation in a rat model of Parkinson's disease
Author(s) -
Li LiBo,
Han LingNa,
Zhang QiaoJun,
Sun YiNa,
Wang Yong,
Feng Jie,
Zhang Li,
Wang Tao,
Chen Li,
Liu Jian
Publication year - 2014
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.22226
Subject(s) - hippocampal formation , diagonal band of broca , neuroscience , bursting , stimulation , pars compacta , parvalbumin , premovement neuronal activity , hippocampus , chemistry , substantia nigra , lesion , agonist , inhibitory postsynaptic potential , medicine , endocrinology , psychology , receptor , central nervous system , biology , dopamine , basal forebrain , dopaminergic , psychiatry
The parvalbumin (PV)‐positive neurons in the medial septum‐diagonal band of Broca complex (MS‐DB) play an important role in the generation of hippocampal theta rhythm involved in cognitive functions. These neurons in this region express a high density of 5‐HT 1A receptors which regulate the neuronal activity and consequently affect the theta rhythm. In this study, we examined changes in the theta‐related firing activity of PV‐positive neurons in the MS‐DB, their response to 5‐HT 1A receptor stimulation and the corresponding hippocampal theta rhythm, and the density of PV‐positive neurons and their co‐localization with 5‐HT 1A receptors in rats with 6‐hydroxydopamine lesions of the substantia nigra pars compacta (SNc). The lesion of the SNc decreased the rhythmically bursting activity of PV‐positive neurons and the peak frequency of hippocampal theta rhythm. Systemic administration of 5‐HT 1A receptor agonist 8‐OH‐DPAT (0.5–128 µg/kg, i.v.) inhibited the firing rate of PV‐positive neurons and disrupted rhythmically bursting activity of the neurons and the theta rhythm in sham‐operated and the lesioned rats, respectively. The cumulative doses producing inhibition and disruption in the lesioned rats were higher than that of sham‐operated rats. Furthermore, local application of 8‐OH‐DPAT (0.005 μg) in the MS‐DB also inhibited the firing rate of PV‐positive neurons and disrupted their rhythmically bursting activity in sham‐operated rats, while having no effect on PV‐positive neurons in the lesioned rats. The lesion of the SNc decreased the density of PV‐positive neurons in the MS‐DB, and percentage of PV‐positive neurons expressing 5‐HT 1A receptors. These results indicate that the lesion of the SNc leads to suppression of PV‐positive neurons in the MS‐DB and hippocampal theta rhythm. Furthermore, the lesion decreases the response of these neurons to 5‐HT 1A receptor stimulation, which attributes to dysfunction and/or down‐regulation of 5‐HT 1A receptor expression on these neurons. These changes may be involved in cognitive impairments of Parkinson's disease. © 2013 Wiley Periodicals, Inc.