Postnatal development of electrophysiological and morphological properties in layer 2/3 and layer 5 pyramidal neurons in the mouse primary visual cortex.

Eye-opening is a critical point for laminar maturation of pyramidal neurons (PNs) in primary visual cortex. Knowing both the intrinsic properties and morphology of PNs from the visual cortex during development is crucial to contextualize the integration of visual inputs at different age stages. Few studies have reported changes in intrinsic excitability in these neurons but were restricted to only one layer or one stage of cortical development.

Chloride accumulation in mammalian olfactory sensory neurons.

The generation of an excitatory receptor current in mammalian olfactory sensory neurons (OSNs) involves the sequential activation of two distinct types of ion channels: cAMP-gated Ca(2+)-permeable cation channels and Ca(2+)-gated Cl(-) channels, which conduct a depolarizing Cl(-) efflux. This unusual transduction mechanism requires an outward-directed driving force for Cl(-), established by active accumulation of Cl(-) within the lumen of the sensory cilia. We used two-photon fluorescence lifetime imaging microscopy of the Cl(-)-sensitive dye 6-methoxy-quinolyl acetoethyl ester to measure the intracellular Cl(-) concentration in dendritic knobs of OSNs from mice and rats.

The complex of cGMP-gated channel and Na+/Ca2+, K+ exchanger in rod photoreceptors.

Ca2+ is an important signal ion in photoreceptors for recovery after excitation and light adaptation. It enters the outer segment as a minor fraction of the dark current through cGMP-gated channels and is extruded in the same cell compartment by Na+/Ca2+, K+ exchange. Channel and exchanger are located exclusively in the plasma membrane, but not in the cytoplasmic membrane stack, the discs, which contain the visual pigment rhodopsin.

Binding of the retinal rod Na+/Ca2+-K+ exchanger to the cGMP-gated channel indicates local Ca(2+)-signaling in vertebrate photoreceptors.

Ca(2+) ions enter the outer segment of rod or cone photoreceptors exclusively through the cGMP-gated channel and are extruded by the Na(+)/Ca(2+)-K(+) exchanger. Recent evidence indicates that in the plasma membrane, the Na(+)/Ca(2+)-K(+) exchanger is associated with the cGMP-gated channel. In this contribution, the possible physiologic significance of this protein complex is considered.

Mutual inhibition of the dimerized Na/Ca-K exchanger in rod photoreceptors.

In the dark, rod photoreceptors sustain a continuous influx of Na and Ca ions through the cGMP-gated channels of the rod outer segments (ROS). Whereas Na ions are extruded in the inner segment by the Na-pump, Ca ions are extruded already in the ROS by Na/Ca-K exchange. Our previous findings indicate that in the ROS plasma membrane, exchanger and channel form a complex of two exchangers associated per channel.