ABSTRACT
This chapter gives an overview of connexin hemichannels and their potential roles under normal and pathological conditions, and discusses common methods used for assessing the functional state of connexin hemichannels. It introduces hypoxic acidic ion shifted ringer (HAIR) solution as an alternative means to assess hemichannel opening during ischemia injury in vitro, and separately during post-ischemia reperfusion, by quantifying ATP release. The chapter examines the contribution of pannexin channels during ischemic injury and reperfusion. It outlines in vitro model for differentiating connexin hemichannels and pannexin channel activities during ischemic injury and during reperfusion. The chapter also outlines the results using the connexin mimetic peptide hemichannel blocker Peptide5 and the Pannexin1 channel blocker Probenecid, with this model enabling the separation of connexin hemichannels and pannexin channel roles in a reproducible manner. The permeability of the pannexin channels to the ATP has been demonstrated in excised patches following mechanical stress.
