Rat brain membrane-bound delta opioid receptor: loss and reactivation of binding on dialysis and aging at low temperature.
A change in the environment of rat brain membranes by dialysis from phosphate buffered saline (PBS) to 10 mM potassium phosphate (pH 7.2) led to a 35% loss in delta opioid receptor binding, while alteration of membrane structure on freezing at -20 degrees C for 55 days led to 85% loss of receptor binding. The dialysate, 200 mM KCI and NaCl restored receptor binding lost on dialysis. This K+ and Na+ restabilization of the receptor can be through cation-pi bonding, interactions that are suited to the lipid bilayer. In membranes stored at -20 degrees C, the loss of binding is attributed to increased membrane fluidity by phospholipase A2 action on membrane phospholipids, resulting in an increase of free fatty acids. K+ but not Na+ restabilization of these membrane receptors may be due to the ability of K+ to decrease membrane fluidity.
Christadoss
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Neurochemistry Laboratory, Department of Neurological Sciences, CMC Hospital, Vellore, TN, India.
Oommen
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D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D003956:Dialysis; D004305:Dose-Response Relationship, Drug; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
D010743:Phospholipids; D017465:Receptors, Opioid, delta; D012964:Sodium; D010741:Phospholipases A; D054467:Phospholipases A2; D011188:Potassium