Astrocytes form extensive intercellular networks through gap junctions to support both biochemical and electrical coupling between adjacent cells. ATP-sensitive K(+) (K(ATP)) channels couple cell metabolic state to membrane excitability and are enriched in glial cells. Activation of astrocytic mitochondrial K(ATP) (mitoK(ATP)) channel regulates certain astrocytic functions. However, less is kno...

In the heart, intercellular gap junction channels constructed from connexin molecules are crucial for conduction of the electric impulse. Cardiomyocytes can be interconnected by channels composed of three types of connexin proteins: Cx40, Cx43 or Cx45. In mammalian hearts, these three isoforms are regionally differently expressed and even between the species differences exist. Each of these cha...

Volatile anesthetics alter tissue excitability by decreasing the extent of gap junction-mediated cell-cell coupling and by altering the activity of the channels that underlie the action potential. In the present study, we demonstrate, using dual whole-cell voltage-clamp techniques, that coexpression of connexin (Cx) 40 and Cx43 rendered cells more sensitive to uncoupling by halothane than cells...

Charged amino acid residues in the amino terminus of gap junction forming proteins (connexins) form part, if not all, of the transjunctional voltage sensor of gap junction channels and play a fundamental role in ion permeation. Results from studies of the voltage dependence of N-terminal mutants predict that residues 1-10 of Group I connexins lie within the channel pore and that the N-terminus ...

39 The quantitative relationship between presynaptic calcium influx and transmitter 40 release critically depends on the spatial coupling of presynaptic calcium channels to 41 synaptic vesicles. When there is a close association between calcium channels and 42 synaptic vesicles, the flux through a single open calcium channel may be sufficient to 43 trigger transmitter release. With increasing s...

Gap junctions represent a ubiquitous and integral part of multicellular organisms, providing the only conduit for direct exchange of nutrients, messengers and ions between neighboring cells. However, at the molecular level we have limited knowledge of their endogenous permeants and selectivity features. By probing the accessibility of systematically substituted cysteine residues to thiol blocke...