New Proof for Astrocytes Having L-type Calcium Channels

The laser scanning confocal microscope and fluorescence spectrophotometer were used to investigate the effects of the L-type calcium channel agonist 1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl] pyridine-3- carboxylic acid [(±)-Bay k8644] and antagonist nimodipine on intra-cellular calcium concentration ([Ca²⁺]i ) of cultured mouse astrocyetes. The results showed that Bay K8644 can significantly increase the [Ca²⁺]i in cultured astrocytes at doses of 0.0001, 0.001 and 0.01 mmol/L, whereas nimodipine can decrease the [Ca²⁺]i at doses of 0.001, 0.01 and 0.1 mmol/L. Nimodipine can also decrease the elevation of [Ca²⁺]i elicited by KCl. Our results suggest that the effects of L-type calcium channel agonist and antagonist on astrocyes are the same as those on neurons, it indicates that astrocytes also have L-type calcium channels.

Keywords
Astrocyte; Intra-cellular calcium concentration([Ca²⁺]i); Nimodipine; Bay k8644; L-type calcium channel