The native T-type calcium current in relay neurons of the primate thalamus

The generation of thalamic bursts depends upon calcium currents that flow through transiently open (T)-type calcium channels. In this study, we characterized the native T-type calcium current underlying thalamic burst responses in the macaque monkey. Current clamp recordings from lateral geniculate...

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Bibliographic Details
Published in:Neuroscience 2006-01, Vol.141 (1), p.453-461
Main Authors: Alexander, G.M., Carden, W.B., Mu, J., Kurukulasuriya, N.C., McCool, B.A., Nordskog, B.K., Friedman, D.P., Daunais, J.B., Grant, K.A., Godwin, D.W.
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
burst
Calcium Channels, T-Type - classification
Calcium Channels, T-Type - genetics
Calcium Channels, T-Type - physiology
cynomolgus macaque
Dose-Response Relationship, Radiation
Electric Stimulation - methods
epilepsy
EPSP
Eye and associated structures. Visual pathways and centers. Vision
Fundamental and applied biological sciences. Psychology
Gene Expression - physiology
Geniculate Bodies - cytology
Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy
In Vitro Techniques
lateral geniculate nucleus
Macaca
Macaca fascicularis
Medical sciences
Membrane Potentials - physiology
Membrane Potentials - radiation effects
monkey
Nervous system (semeiology, syndromes)
Neurology
Neurons - physiology
Primates
Reverse Transcriptase Polymerase Chain Reaction - methods
RNA, Messenger - metabolism
Vertebrates: nervous system and sense organs
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Summary:The generation of thalamic bursts depends upon calcium currents that flow through transiently open (T)-type calcium channels. In this study, we characterized the native T-type calcium current underlying thalamic burst responses in the macaque monkey. Current clamp recordings from lateral geniculate nucleus (LGN) slices showed characteristic burst responses when relay cells were depolarized from relatively hyperpolarized membrane potentials. These bursts could also be elicited by stimulation of excitatory synaptic inputs to LGN cells. Under voltage clamp conditions, the inactivation kinetics of native currents recorded from primate LGN neurons showed consistency with T-type currents recorded in other mammals and in expression systems. Real-time reverse transcriptase PCR performed on RNA isolated from the LGN (including tissues isolated from magnocellular and parvocellular laminae) detected voltage-dependent calcium channel (Cav) 3.1, Cav 3.2, and Cav 3.3 channel transcripts. Cav 3.1 occurred at relatively higher expression than other isoforms, consistent with in situ hybridization studies in rats, indicating that the molecular basis for burst firing in thalamocortical systems is an important conserved property of primate physiology. Since thalamic bursts have been observed during visual processing as well as in a number of CNS disorders, studies of the expression and modulation of these currents at multiple levels are critical for understanding their role in vision and for the discovery of new treatments for disruptions of thalamic rhythms.
ISSN:0306-4522
1873-7544
DOI:10.1016/j.neuroscience.2006.03.042