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Histamine modulates spinal motoneurons and locomotor circuits
Author(s) -
Coslovich Tamara,
Brumley Michele R.,
D'Angelo Giuseppe,
Della Mora Alberto,
Swann Hillary E.,
Ortolani Fulvia,
Taccola Giuliano
Publication year - 2018
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.24195
Subject(s) - depolarization , histamine , neuroscience , chemistry , electrophysiology , hyperpolarization (physics) , tonic (physiology) , membrane potential , rheobase , bursting , histamine h3 receptor , biology , pharmacology , biophysics , antagonist , receptor , biochemistry , organic chemistry , nuclear magnetic resonance spectroscopy
Spinal motoneurons and locomotor networks are regulated by monoamines, among which, the contribution of histamine has yet to be fully addressed. The present study investigates histaminergic regulation of spinal activity, combining intra‐ and extracellular electrophysiological recordings from neonatal rat spinal cord in vitro preparations. Histamine dose‐dependently and reversibly generated motoneuron depolarization and action potential firing. Histamine (20 µM) halved the area of dorsal root reflexes and always depolarized motoneurons. The majority of cells showed a transitory repolarization, while 37% showed a sustained depolarization maintained with intense firing. Extracellularly, histamine depolarized ventral roots (VRs), regardless of blockage of ionotropic glutamate receptors. Initial, transient glutamate‐mediated bursting was synchronous among VRs, with some bouts of locomotor activity in a subgroup of preparations. After washout, the amplitude of spontaneous tonic discharges increased. No desensitization or tachyphylaxis appeared after long perfusion or serial applications of histamine. On the other hand, histamine induced single motoneuron and VR depolarization, even in the presence of tetrodotoxin (TTX). During chemically induced fictive locomotion (FL), histamine depolarized VRs. Histamine dose‐dependently increased rhythm periodicity and reduced cycle amplitude until near suppression. This study demonstrates that histamine induces direct motoneuron membrane depolarization and modulation of locomotor output, indicating new potential targets for locomotor neurorehabilitation.