Spike frequency adaptation is developmentally regulated in substantia nigra pars compacta dopaminergic neurons

• Published in: Neuroscience Vol. 192; pp. 1 - 10
• Main Authors: Vandecasteele, M, Deniau, J.-M, Venance, L
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 29.09.2011; Elsevier; Elsevier - International Brain Research Organization
• Subjects: Action Potentials - physiology; Adaptation, Physiological - physiology; Animals; Biological and medical sciences; dopaminergic neuron; Dopaminergic Neurons - physiology; Female; Fundamental and applied biological sciences. Psychology; Immunohistochemistry; in vitro electrophysiology; Life Sciences; Male; Neurology; Organ Culture Techniques; Patch-Clamp Techniques; post-natal development; Rats; Rats, Sprague-Dawley; SK current; spike frequency adaptation; Substantia Nigra - growth & development; Substantia Nigra - physiology; substantia nigra pars compacta; Vertebrates: nervous system and sense organs; interspike interval; F final; initial instantaneous firing frequency; small conductance calcium-activated potassium; AHP; SNc; in vitro electrophysiology; final instantaneous firing frequency; dopaminergic neuron; fAHP; action potential; F init; AP; SFA; spike frequency adaptation; hyperpolarization-activated depolarizing current; substantia nigra pars compacta; fast afterhyperpolarization; post-natal development; SK; SK current; afterhyperpolarization; ISI; Ih; Ffinal; Finit; Central nervous system; Electrophysiology; In vitro; Encephalon; Locus niger; Development; Dopaminergic neuron; Adaptation; Action Potentials, Adaptation, Physiological, Animals, Dopaminergic Neurons, Female, Immunohistochemistry, Male, Organ Culture Techniques, Patch-Clamp Techniques, Rats, Rats, Sprague-Dawley, Substantia Nigra
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2011.07.017

Abstract Dopaminergic neurons of the substantia nigra pars compacta play a key role in the modulation of basal ganglia and provide a reward-related teaching signal essential for adaptative motor control. They are generally considered as a homogenous population despite several chemical and electrophysiological heterogeneities, which could underlie different preferential patterns of activity and/or different roles. Using whole-cell patch-clamp recordings in juvenile rat brain slices, we observed that the evoked activity of dopaminergic neurons displays variable spike frequency adaptation patterns. The intensity of spike frequency adaptation decreased during post-natal development. The adaptation was associated with an increase in the initial firing frequency due to faster kinetics of the afterhyperpolarization component of the spike. Adaptation was enhanced when small conductance calcium-activated potassium (SK) channels were blocked with bath application of apamine. Lastly, spike frequency adaptation of the evoked discharge was associated with more irregularity in the spontaneous firing pattern. Altogether these results show a developmental heterogeneity and electrophysiological maturation of substantia nigra dopaminergic neurons.