Manko 2013 Acta Physiol (Oxf)
| Manko BO, Manko VV (2013) Mechanisms of respiration intensification of rat pancreatic acini upon carbachol-induced Ca(2+) release. Acta Physiol (Oxf) 208:387-99. |
Manko BO, Manko VV (2013) Acta Physiol (Oxf)
Abstract: AIM:
Acetylcholine as one of the main secretagogues modulates mitochondrial functions in acinar pancreacytes, presumably due to increase in ATP hydrolysis or Ca(2+) transport into mitochondria. The aim of this work was to investigate the mechanisms of carbachol (CCh) action on respiration and oxidative phosphorylation of isolated pancreatic acini.
METHODS:
Respiration of intact or permeabilized rat pancreatic acini was studied at 37 °C using a Clark oxygen electrode.
RESULTS:
Respiration rate of isolated acini in rest was 0.27 ± 0.01 nmol O2 s(-1) 10(-6) cells. Addition of 10 μM CCh into respiration chamber evoked biphasic stimulation of respiration. Rapid increase of respiration by 20.1% lasted for approx. 1 min, followed by decrease to level by 11.5% higher than control. Addition of 1 μm CCh caused monophasic increase by 11.5%. Preincubation (5 min) with 1 or 10 μm CCh elevated respiration rate by 12.5 or 11.2% respectively. FCCP prevented the effect of CCh. Preincubation with 1 (but not 10) μm CCh increased FCCP-uncoupled respiration rate. Thapsigargin slightly elevated respiration, but ryanodine did not. Application of 2-aminoethoxydiphenyl borate or ruthenium red prevented the effects of CCh on respiration, while oligomycin abolished them. Preincubation with 1 μm CCh prior to cell permeabilization increased respiration rate at pyruvate+malate oxidation, but not at succinate oxidation. In contrast, preincubation with 10 μm CCh decreased pyruvate+malate oxidation.
CONCLUSION:
Medium CCh dose (1 μm) intensifies respiration and oxidative phosphorylation of acinar pancreacytes by feedforward mechanism via Ca(2+) transport into mitochondria and activation of Ca(2+) /ADP-sensitive mitochondrial dehydrogenases. Prolonged action of high CCh dose (10 μm) might impair mitochondrial functions. • Keywords: Ca2+, carbachol, mitochondria, pancreatic acini, respiration
Labels: MiParea: Respiration, mt-Medicine, mt-Awareness
Organism: Rat
Tissue;cell: Islet cell;pancreas;thymus
Preparation: Permeabilized cells
Regulation: Calcium Coupling state: LEAK, OXPHOS, ETS"ETS" is not in the list (LEAK, ROUTINE, OXPHOS, ET) of allowed values for the "Coupling states" property.
