Abstract
Parotid gland membranes labelled with [3H]inositol were challenged with the cholinergic agonist, carbamylcholine, or with epinephrine in the presence of propranolol. Both agonists caused a significant breakdown of labelled phosphoinositides (17.5%) in membranes suspended in Krebs-Ringer bicarbonate buffer. This effect was abolished by the respective antagonists, atropine or phentolamine. The carbamylcholine-induced breakdown of labelled phosphoinositides did not require cytosol. The addition of cytosol alone, or the exposure of membranes to a medium of low ionic strength caused a significant breakdown of phosphoinositides (10-40%). No further breakdown due to the addition of carbamylcholine was observed under these conditions. It is suggested that neurotransmitter-induced breakdown of phosphoinositides is effected by membrane-associated enzyme(s) and can be observed only in a medium of high ionic strength.
Original language | English |
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Pages (from-to) | 278-282 |
Number of pages | 5 |
Journal | FEBS Letters |
Volume | 178 |
Issue number | 2 |
DOIs | |
State | Published - 10 Dec 1984 |
Keywords
- Cholinergic receptor
- Parotid membrane
- Phosphoinositide breakdown