Bipolar cells convey information through the retina via graded changes in their membrane potential and modulate transmitter release through the influx of calcium via L-type calcium channels. However, the molecular identity of the α1 subunit has not been confirmed. We report the presence of the newly cloned α1F subunit in mouse bipolar cell synaptic terminals. The α1F subunits are localized to hot spots, possibly corresponding to active zones. We also report the physiological properties of two calcium currents present in mouse bipolar cells, a low-voltage-activated L-type current and a low-voltage-activated T-type calcium current. The physiological properties of the T-type current suggest that it is completely inactivated under physiological conditions. The L-type current may be mediated by the α1F subunit, and influx of calcium through the α1F channel may control neurotransmitter release from the bipolar cell terminal.
- Alpha 1F
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience