ISSN:
1432-2013
Keywords:
Helix bursting neurons
;
Calcium imaging
;
Calcium buffering
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Bursting pacemaker neurons of the snail Helix pomatia were voltage-clamped and Ca currents in response to depolarizing steps were recorded. Simultaneously, changes in intracellular Ca concentrations were measured using the fluorescent dye fura-2 and a highly sensitive digital camera. Ca influx through voltage-gated channels induced a spatially non-uniform increase in intracellular Ca. The Ca signals decayed with a time constant of about 5 s. By increasing the concentration of the indicator dye, its Ca-buffering capacity was enhanced and Ca transients in response to depolarization were diminished. Thereby, the endogenous Ca buffer capacity could be determined and was calculated to be about 480 buffered ions for every free Ca ion. The buffer capacity did not vary significantly with the amount of Ca influx within the range tested, suggesting that the buffer is not saturated at Ca concentrations of up to 1μM.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00374877
