Fast imaging of [Ca]i reveals presence of voltage-gated calcium channels in
dendritic spines of cultured hippocampal neurons.
Segal, Menahem.
Department of Neurobiology, The Weizmann Institute, Rehovot, 76100,
Israel.
APStracts 2:0123N, 1995.
SUMMARY AND CONCLUSIONS
Cultured hippocampal neurons were recorded with a patch pipette containing 100
[mu] M of the calcium indicator Fluo-3 and one of their dendrites, carrying
dendritic spines, was visualized with a 100x, 1.3NA oil objective. Calcium
spikes were evoked by depolarizing the somata and changes in free dendrite and
spine calcium concentrations ([Ca]d and [Ca]s, respectively) were monitored
with a cooled CCD camera, acquiring images at a rate of 17-20msec/frame. In
the majority of spine/dendrite pairs, [Ca]s rose faster, and to a higher level
than the adjacent [Ca]d. Likewise, topical application of glutamate evoked a
faster and larger [Ca]s than [Ca]d change. The rise of [Ca]i in response to a
depolarizing current pulse, but not in response to glutamate, was reduced in
the presence of the calcium antagonist, verapamil in both dendrites and
spines. It is suggested that dendritic spines possess voltage gated calcium
channels.
Received 16 December 1994; accepted in final form 3 April 1995.
APS Manuscript Number J784-4.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 1 May 1995.