Original scientific paper
https://doi.org/10.2478/10004-1254-60-2009-1917
Comparative Effects of Calcium Channel Blockers, Autonomic Nervous System Blockers, and Free Radical Scavengers on Diazinon-Induced Hyposecretion of Insulin from Isolated Islets of Langerhans in Rats
Nazila Pourkhalili
; Pharmaceutical Sciences Branch, Islamic Azad University, Tehran, Iran
Shirin Pournourmohammadi
; Institute of Medicinal Plants, ACECR, Tehran, Iran
Fatemeh Rahimi
; Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University, of Medical Sciences, Tehran, Iran
Sanaz Vosough-Ghanbari
; Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University, of Medical Sciences, Tehran, Iran
Maryam Baeeri
; Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University, of Medical Sciences, Tehran, Iran
Seyed Nasser Ostad
; Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University, of Medical Sciences, Tehran, Iran
Mohammad Abdollahi
; Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University, of Medical Sciences, Tehran, Iran
Abstract
Hyperglycaemia has been observed with exposure to organophosphate insecticides. This study was designed to compare the effects of calcium channel blockers, alpha-adrenergic, beta-adrenergic, and muscarinic receptor blockers, and of free radical scavengers on insulin secretion from diazinon-treated islets of Langerhans isolated from the pancreas of rats using standard collagenase digestion, separation by centrifugation, and hand-picking technique. The islets were then cultured in an incubator at 37 °C and 5 % CO2. In each experimental set 1 mL of 8 mmol L-1 glucose plus 125 µg mL-1 or 625 µg mL-1 of diazinon were added, except for the control group, which received 8 mmol L-1 glucose alone. The cultures were then treated with one of the following: 30 µmol L-1 atropine, 100 µmol L-1 ACh + 10 µmol L-1 neostigmine, 0.1 µmol L-1 propranolol, 2 µmol L-1 nifedipine, 50 µmol L-1 phenoxybenzamine, or 10 µmol L-1 alphatocopherol. In all experiments, diazinon significantly reduced glucose-stimulated insulin secretion at both doses, showing no dose dependency, as the average inhibition for the lower dose was 62.20 % and for the higher dose 64.38 %. Acetylcholine and alpha-tocopherol restored, whereas atropine potentiated diazinoninduced hyposecretion of insulin. Alpha-, beta- and calcium channel blockers did not change diazinoninduced effects. These findings suggest that diazinon affects insulin secretion mainly by disturbing the balance between free radicals and antioxidants in the islets of Langerhans and by inducing toxic stress.
Keywords
organophosphates; oxidative stress; pancreas; rats
Hrčak ID:
38391
URI
Publication date:
12.6.2009.
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