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Perez-García P, Pardillo-Díaz R, Geribaldi-Doldán N, Gómez-Oliva R, Domínguez-García S, Castro C, Nunez-Abades P, Carrascal L. Refinement of Active and Passive Membrane Properties of Layer V Pyramidal Neurons in Rat Primary Motor Cortex During Postnatal Development. Front Mol Neurosci 2021; 14:754393. [PMID: 34924951 PMCID: PMC8671142 DOI: 10.3389/fnmol.2021.754393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
Achieving the distinctive complex behaviors of adult mammals requires the development of a great variety of specialized neural circuits. Although the development of these circuits begins during the embryonic stage, they remain immature at birth, requiring a postnatal maturation process to achieve these complex tasks. Understanding how the neuronal membrane properties and circuits change during development is the first step to understand their transition into efficient ones. Thus, using whole cell patch clamp recordings, we have studied the changes in the electrophysiological properties of layer V pyramidal neurons of the rat primary motor cortex during postnatal development. Among all the parameters studied, only the voltage threshold was established at birth and, although some of the changes occurred mainly during the second postnatal week, other properties such as membrane potential, capacitance, duration of the post-hyperpolarization phase or the maximum firing rate were not defined until the beginning of adulthood. Those modifications lead to a decrease in neuronal excitability and to an increase in the working range in young adult neurons, allowing more sensitive and accurate responses. This maturation process, that involves an increase in neuronal size and changes in ionic conductances, seems to be influenced by the neuronal type and by the task that neurons perform as inferred from the comparison with other pyramidal and motor neuron populations.
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Affiliation(s)
- Patricia Perez-García
- Department of Physiology, School of Pharmacy, University of Seville, Seville, Spain.,Division of Physiology, School of Medicine, University of Cádiz, Cádiz, Spain
| | - Ricardo Pardillo-Díaz
- Division of Physiology, School of Medicine, University of Cádiz, Cádiz, Spain.,Biomedical Research and Innovation Institute of Cádiz (INiBICA), Cádiz, Spain
| | - Noelia Geribaldi-Doldán
- Biomedical Research and Innovation Institute of Cádiz (INiBICA), Cádiz, Spain.,Department of Human Anatomy and Embriology, University of Cádiz, Cádiz, Spain
| | - Ricardo Gómez-Oliva
- Division of Physiology, School of Medicine, University of Cádiz, Cádiz, Spain.,Biomedical Research and Innovation Institute of Cádiz (INiBICA), Cádiz, Spain
| | - Samuel Domínguez-García
- Division of Physiology, School of Medicine, University of Cádiz, Cádiz, Spain.,Biomedical Research and Innovation Institute of Cádiz (INiBICA), Cádiz, Spain
| | - Carmen Castro
- Division of Physiology, School of Medicine, University of Cádiz, Cádiz, Spain.,Biomedical Research and Innovation Institute of Cádiz (INiBICA), Cádiz, Spain
| | - Pedro Nunez-Abades
- Department of Physiology, School of Pharmacy, University of Seville, Seville, Spain.,Biomedical Research and Innovation Institute of Cádiz (INiBICA), Cádiz, Spain
| | - Livia Carrascal
- Department of Physiology, School of Pharmacy, University of Seville, Seville, Spain.,Biomedical Research and Innovation Institute of Cádiz (INiBICA), Cádiz, Spain
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Portillo F, Moreno-López B. Nitric oxide controls excitatory/inhibitory balance in the hypoglossal nucleus during early postnatal development. Brain Struct Funct 2020; 225:2871-84. [PMID: 33130922 DOI: 10.1007/s00429-020-02165-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 10/17/2020] [Indexed: 01/18/2023]
Abstract
Synaptic remodeling during early postnatal development lies behind neuronal networks refinement and nervous system maturation. In particular, the respiratory system is immature at birth and is subjected to significant postnatal development. In this context, the excitatory/inhibitory balance dramatically changes in the respiratory-related hypoglossal nucleus (HN) during the 3 perinatal weeks. Since, development abnormalities of hypoglossal motor neurons (HMNs) are associated with sudden infant death syndrome and obstructive sleep apnea, deciphering molecular partners behind synaptic remodeling in the HN is of basic and clinical relevance. Interestingly, a transient expression of the neuronal isoform of nitric oxide (NO) synthase (NOS) occurs in HMNs at neonatal stage that disappears before postnatal day 21 (P21). NO, in turn, is a determining factor for synaptic refinement in several physiopathological conditions. Here, intracerebroventricular chronic administration (P7–P21) of the broad spectrum NOS inhibitor l-NAME (N(ω)-nitro-l-arginine methyl ester) differentially affected excitatory and inhibitory rearrangement during this neonatal interval in the rat. Whilst l-NAME led to a reduction in the number of excitatory structures, inhibitory synaptic puncta were increased at P21 in comparison to administration of the inactive stereoisomer d-NAME. Finally, l-NAME decreased levels of the phosphorylated form of myosin light chain in the nucleus, which is known to regulate the actomyosin contraction apparatus. These outcomes indicate that physiologically synthesized NO modulates excitatory/inhibitory balance during early postnatal development by acting as an anti-synaptotrophic and/or synaptotoxic factor for inhibitory synapses, and as a synaptotrophin for excitatory ones. The mechanism of action could rely on the modulation of the actomyosin contraction apparatus.
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