Hypoxia Enhances [³H]Noradrenaline Release Evoked by Nicotinic Receptor Activation from the Human Neuroblastoma SH‐SY5Y

Abstract

We have used the human sympathetic neuronal line SH-SY5Y to investigate the effects of hypoxia on noradrenaline (NA) release evoked by either raised [K~}O (100 mM) or the nicotinic acetylcholine receptor (nAChR) agonist dimethyiphenylpiperazinium iodide (DMPP). NA release was monitored by loading cells with [3H}NAand collecting effluent fractions from perfused cells kept in a sealed perifusion chamber. Cells were challenged twice with either stimulus and release was expressed as that evoked by the second challenge as a fraction of that evoked by the first. K~-evokedrelease was unaffected by hypoxia (P0 2 30-38 mm Hg), but release evoked by DMPP was significantly increased. For both stimuli, replacement of Ca 2~0with 1 mM EGTA abolished NA release. K~-evokedrelease was also dramatically reduced in the presence of 200 ,uM Cd

Overexpression of the myristoylated alanine‐rich C kinase substrate decreases uptake and K+‐evoked release of noradrenaline in the human neuroblastoma SH‐SY5Y

“…Carbachol‐evoked release of NA from SH‐SY5Y is completely inhibited by the muscarinic antagonist atropine (Murphy et al ., 1991). This excludes the possibility of carbachol acting via the nicotinic receptor shown previously to be present in SH‐SY5Y (Vaughan et al ., 1993; Wade et al ., 1998). The muscarinic receptor involved has been shown to be a M 3 receptor subtype (Murphy et al ., 1991).…”