Characteristics of voltage sensitive calcium channels in dendrites of cultured rat cerebellar neurons.
We examined the effects of various pharmacological agents on the Ca2+ channels existing in the dendrites of cultured rat cerebellar neurons. The cultures consisted of Purkinje cells and non-Purkinje cells (deep cerebellar nuclear neurons and other non-granule neurons). Changes in intracellular free calcium concentration, [Ca2+]i, were monitored by digital imaging microfluorimetry using fura-2 as the indicator dye. In the Purkinje cell population increases in dendritic [Ca2+]i evoked by brief pulses of high K+ were very effectively blocked by (> 80%) by omega-Aga-IVA at low concentrations. Nimodipine and omega-conotoxins GVIA and MVIIC only blocked small components of the [Ca2+]i rise. In the non-Purkinje cells, omega-Aga-IVA was much less effective. omega-Conotoxin-GVIA blocked somewhat more and nimodipine blocked a similar percentage of the [Ca2+]i rise. omega-Conotoxin-MVIIC was quite ineffective in these cells. The results are discussed in terms of the types of voltage sensitive Ca2+ channels existing in the dendrites of these cells.
Bindokas
V P
VP
Department of Pharmacological and Physiological Sciences, University of Chicago, IL 60637.
Brorson
J R
JR
Miller
R J
RJ
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004594:Electrophysiology; D005470:Fluorometry; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D011689:Purkinje Cells / Q000187:drug effects / Q000378:metabolism; D051381:Rats
D002121:Calcium Channel Blockers; D015220:Calcium Channels