ISSN:
1432-2013
Keywords:
Salivary gland
;
Intracellular pH
;
31P NMR spectroscopy
;
Acetylcholine
;
Amiloride
;
DIDS
;
Na+−H+ exchange
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Intracellular pH (pHi) was measured in the isolated, perfused rabbit mandibular salivary gland by31P NMR spectroscopy. In the unstimulated gland perfused with HCO 3 − /CO2-buffered Ringer's solution, pHi was 7.27±0.01. Continuous stimulation with acetylcholine elicited dose- and time-dependent changes in pHi. 10−6 mol/l acetylcholine caused a brief intracellular acidosis (−0.19±0.06 pH units) followed by an increase in pHi to a more alkaline steady-state value (7.33±0.02). In the absence of perfusate HCO 3 − or in the presence of 10−4 mol/l DIDS (4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid), the transient acidosis was abolished and pHi increased rapidly to give a sustained alkalosis (7.49±0.03 and 7.44±0.03 respectively). In the presence of 10−3 mol/l amiloride, the response to acetylcholine was a rapid decrease in pHi to 7.02±0.02. The data suggest that, during perfusion with HCO 3 − /CO2-buffered solutions, stimulation with acetylcholine results in a transient loss of HCO 3 − from the acinar cells (causing a transient acidosis), and, independently, the activation of Na+−H+ exchange (causing a sustained alkalosis). In the unstimulated gland, DIDS and the HCO 3 − -free perfusate caused decreases in pHi to 7.12±0.02 and 7.04±0.01 respectively. In contrast, amiloride had little effect. The relatively high value of pHi maintained by the unstimulated gland is therefore probably not due to Na+−H+ exchange.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00580964
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