Lead Exposure Changes Gastric Acid Secretion in Rat: Role of Nitric Oxide (NO)
,
Abstract
Sub chronic exposure to lead in rats slows gastric emptying, but little is known about the effects of lead on gastric secretion. This study was designed to investigate the effects of lead on gastric acid secretion and its possible mechanisms in rats. Lead acetate was dissolved in drinking water in a concentration of 1%. Sodium acetate-containing water with a molar concentration similar to lead was also prepared. We had nine groups of animals (n=8); four of them were exposed to lead for 1, 2, 3, and 4 weeks (Pb1, Pb2, Pb3 and Pb4 groups, respectively). Sodium acetate solution was given to another four groups for 1, 2, 3, and 4 weeks (Na1, Na2, Na3 and Na4 groups, respectively). Gastric secretion was collected by washout technique and its acid output was measured in the basal (Basal Acid Output, BAO), vogotomy (Vagotomized Acid Output, VAO), and vagally stimulated (Vagally Stimulated Acid Output, VSAO) states using titrator instrument. Nitric oxide (NO) metabolite of gastric tissue was determined by Griess micro assay method to evaluate the possible mechanism of lead effect on gastric secretion. VSAO was significantly less in Pb1 and Pb2 groups than Na1 and Na2 ones respectively (1.75 ± 0.17, 2.10 ± 0.30 vs. 5.79 ± 0.20, 6.18 ± 0.27 µmol/15min) (P=0.001, P=0.001). BAO was significantly more in Pb3 and Pb4 groups than Na3 and Na4 ones respectively (2.77 ± 0.37, 2.80 ± 0.31 vs. 1.73 ± 0.16, 1.79 ± 0.34 µmol/15min) (P=0.01, P=0.02), but it was the same after vagotomy. VSAO was more in Pb3 and Pb4 groups than their Na counterparts (P=0.001, P=0.0001). NO metabolite of gastric tissue was more in all Pb groups in comparison to their Na counterparts (P=0.0001). In this study, it seems that lead exposure, via NO mechanism, has different effects on acid secretion. Nitric oxide in small and large amounts decrease and increase gastric acid secretion, respectively.
Reis MF, Sampaio C, Brantes A, Aniceto P, Melim M, Cardoso L, et al. Human exposure to heavy metals in the vicinity of Portuguese solid waste incinerators: Part 3: biomonitoring of Pb in blood of children under the age of 6 years. Int J Hyg Environ Health 2007;210(3-4):455-9.
Toplan S, Ozcelik D, Gulyasar T, Akyolcu MC. Changes in hemorheological parameters due to lead exposure in female rats. J Trace Elem Med Biol 2004;18(2):179-82.
Tyroler HA. Epidemiology of hypertension as a public health problem: an overview as background for evaluation of blood lead-blood pressure relationship. Environ Health Perspect 1988;78:3-7.
Schwartz J. Lead, blood pressure, and cardiovascular disease in men and women. Environ Health Perspect 1991;91:71-5.
Walsh CT, Ryden EB. The effect of chronic ingestion of lead on gastrointestinal transit in rats. Toxicol Appl Pharmacol 1984;75(3):485-95.
Ryden EB, Walsh CT. The effect of lead on cholinergic contractile function in the rat forestomach. Toxicology 1987;45(1):65-78.
Ghazi-Khansari M, Delfan B, Abdollahi M, Zarrindast MR. Effects of lead acetate exposure on naloxone-inducedjumping behavior in mice. Toxic Substance Mechanisms 1999;18:39-47.
Kang JK, Sul D, Kang JK, Nam SY, Kim HJ, Lee E. Effects of lead exposure on the expression of phospholipid hydroperoxidase glutathione peroxidase mRNA in the rat brain. Toxicol Sci 2004;82(1):228-36. Epub 2004 Mar 10.
Nabavizadeh Rafsanjani F, Vahedian J. The effect of insulin-dependent diabetes mellitus on basal and distention-induced acid and pepsin secretion in rat. Diabetes Res Clin Pract 2004;66(1):1-6.
Rafsanjani FN, Shahrani M, Ardakani ZV, Ardakani MV. Marjoram increases basal gastric acid and pepsin secretions in rat. Phytother Res 2007;21(11):1036-8.
Yang H, Taché Y. PYY in brain stem nuclei induces vagal stimulation of gastric acid secretion in rats. Am J Physiol 1995;268(6 Pt 1):G943-8.
Salim AS. Gastric diversion: a method for H+ output estimation in the rat. Digestion 1988;39(1):47-51.
Rafsanjani FN, Maghouli F, Vahedian J, Esmaeili F. The effects of chronic consumption of heroin on basal and vagal electrical-stimulated gastric acid and pepsin secretion in rat. Saudi Med J 2004;25(10):1356-9.
Baselt RC. Analytical Procedures for Therapeutic Drug Monitoring and Emergency Toxicology. Davis, Calif: Biochemical Publications; 1980. p. 147-8.
Nahrevanian H, Gholizadeh J, Farahmand M, Assmar M, Sharifi K, Ayatollahi Mousavi SA, et al. Nitric oxide induction as a novel immunoepidemiological target in malaria-infected patients from endemic areas of the Islamic Republic of Iran. Scand J Clin Lab Invest 2006;66(3):201-9.
Dijkstra G, van Goor H, Jansen PL, Moshage H. Targeting nitric oxide in the gastrointestinal tract. Curr Opin Investig Drugs 2004;5(5):529-36.
Heydari A, Norouzzadeh A, Khoshbaten A, Asgari A, Ghasemi A, Najafi S, et al. Effects of short-term and subchronic lead poisoning on nitric oxide metabolites and vascular responsiveness in rat. Toxicol Lett 2006;166(1):88-94.
Berg A, Redeen S, Ericson AC, Sjöstrand SE. Nitric oxidean endogenous inhibitor of gastric acid secretion in isolated human gastric glands. BMC Gastroenterol 2004;4:16.
Berg A, Redéen S, Grenegård M, Ericson AC, Sjöstrand SE. Nitric oxide inhibits gastric acid secretion by increasing intraparietal cell levels of cGMP in isolated human gastric glands. Am J Physiol Gastrointest Liver Physiol 2005;289(6):G1061-6.
Shibata N, Matsui H, Yokota T, Matsuura B, Maeyama K, Onji M. Direct effects of nitric oxide on histamine releasefrom rat enterochromaffin-like cells. Eur J Pharmacol 2006;535(1-3):25-33.
Zanner R, Hapfelmeier G, Gratzl M, Prinz C. Intracellular signal transduction during gastrin-induced histamine secretion in rat gastric ECL cells. Am J Physiol Cell Physiol 2002;282(2):C374-82.
Hasebe K, Horie S, Yano S, Watanabe K. Inhibitory effect of N(omega)-nitro-L-arginine on gastric secretion induced by secretagogues and vagal stimulation in the isolated stomach. Eur J Pharmacol 1998;350(2-3):229-36.
Kitamura M, Sugamoto S, Kawauchi S, Kato S, Takeuchi K. Modulation by endogenous nitric oxide of acid secretion induced by gastric distention in rats: enhancement by nitric oxide synthase inhibitor. J Pharmacol Exp Ther 1999;291(1):181-7.
Herring N, Paterson DJ. Nitric oxide-cGMP pathway facilitates acetylcholine release and bradycardia during vagal nerve stimulation in the guinea-pig in vitro. J Physiol 2001;535(Pt 2):507-18.
Herring N, Danson EJ, Paterson DJ. Cholinergic control of heart rate by nitric oxide is site specific. News Physiol Sci 2002;17:202-6.
Hasebe K, Horie S, Komasaka M, Yano S, Watanabe K. Stimulatory effects of nitric oxide donors on gastric acid secretion in isolated mouse stomach. Eur J Pharmacol 2001;420(2-3):159-64.
Hasebe K, Horie S, Noji T, Watanabe K, Yano S. Stimulatory effects of endogenous and exogenous nitric oxide on gastric acid secretion in anesthetized rats. Nitric Oxide 2005;13(4):264-71.
| Files | ||
| Issue | Vol 49, No 1 (2011) | |
| Section | Original Article(s) | |
| Keywords | ||
| Lead Nitric oxide Gastric acid Rats | ||
| Rights and permissions | |
|
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
