PT  - JOURNAL ARTICLE
AU  - T. D. Plant
AU  - C. Schirra
AU  - E. Katz
AU  - O. D. Uchitel
AU  - A. Konnerth
TI  - Single-Cell RT-PCR and Functional Characterization of Ca<sup>2+</sup> Channels in Motoneurons of the Rat Facial Nucleus
AID  - 10.1523/JNEUROSCI.18-23-09573.1998
DP  - 1998 Dec 01
TA  - The Journal of Neuroscience
PG  - 9573--9584
VI  - 18
IP  - 23
4099  - http://www.jneurosci.org/content/18/23/9573.short
4100  - http://www.jneurosci.org/content/18/23/9573.full
SO  - J. Neurosci.1998 Dec 01; 18
AB  - Voltage-dependent Ca2+ channels are a major pathway for Ca2+ entry in neurons. We have studied the electrophysiological, pharmacological, and molecular properties of voltage-gated Ca2+ channels in motoneurons of the rat facial nucleus in slices of the brainstem. Most facial motoneurons express both low voltage-activated (LVA) and high voltage-activated (HVA) Ca2+ channel currents. The HVA current is composed of a number of pharmacologically separable components, including 30% of N-type and ∼5% of L-type. Despite the dominating role of P-type Ca2+ channels in transmitter release at facial motoneuron terminals described in previous studies, these channels were not present in the cell body. Remarkably, most of the HVA current was carried through a new type of Ca2+ channel that is resistant to toxin and dihydropyridine block but distinct from the R-type currents described in other neurons.Using reverse transcription followed by PCR amplification (RT-PCR) with a powerful set of primers designed to amplify all HVA subtypes of the α1-subunit, we identified a highly heterogeneous expression pattern of Ca2+ channel α1-subunit mRNA in individual neurons consistent with the Ca2+ current components found in the cell bodies and axon terminals. We detected mRNA for α1A in 86% of neurons, α1B in 59%, α1C in 18%, α1D in 18%, and α1E in 59%. Either α1A or α1B mRNAs (or both) were present in all neurons, together with various other α1-subunit mRNAs. The most frequently occurring combination was α1Awith α1B and α1E. Taken together, these results demonstrate that the Ca2+ channel pattern found in facial motoneurons is highly distinct from that found in other brainstem motoneurons.