Dopaminergic inhibition of excitatory inputs onto pyramidal tract neurons in cat motor cortex.
The role of dopamine (DA) on motor cortical pyramidal tract neurons (PTNs) was studied in anesthetized cats with in vivo extracellular recordings in response to transcallosal (TC) and ventrolateral (VL) thalamic stimulations. An antidromic PT potential was evoked to recognize PTNs. In most PTNs, iontophoretic application of DA significantly reduced the spike activity exerted by 20 single-pulse stimulations. Both D(1)-like and D(2)-like receptor antagonists blocked (disinhibited) the effect in a similar way regardless of TC and VL stimulations, suggesting colocalization of two receptors. Except for the presence of jittering, the mean latency was usually fixed and short. These findings indicate that ventral midbrain DA imposes an intense suppression in modulating PTNs response to both callosal and thalamocortical excitatory inputs in motor cortex. Such DAergic suppression could play pivotal role to improve motor and sensorimotor signal integration.
Huda
K
K
Department of Neurophysiology, Institute of Equilibrium Research, Gifu University School of Medicine, Tsukasamachi 40, 500-8705, Gifu, Japan. huda@nips.ac.jp
Salunga
T L
TL
Matsunami
K
K
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002415:Cats; D003337:Corpus Callosum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism* / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D009044:Motor Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011712:Pyramidal Tracts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*; D017557:Ventral Tegmental Area / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020651:Ventral Thalamic Nuclei / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D004298:Dopamine