The effects of a single or repeated dermal administration of methyl paration on motor function, learning and memory were investigated in adult female rats and correlated with blood cholinesterase activity. Exposure to a single dose of 50 mg/kg methyl parathion (75% of the dermal LD50) resulted in an 88% inhibition of blood cholinesterase activity and was associated with severe acute toxicity. Spontaneous locomotor activity and neuromuscular coordination were also depressed. Rats treated with a lower dose of methyl parathion, i.e. 6.25 or 12.5 mg/kg, displayed minimal signs of acute toxicity. Blood cholinesterase activity and motor function, however, were depressed initially but recovered fully within 1–3 weeks. There were no delayed effects of a single dose of methyl parathion on learning acquisition or memory as assessed by a step-down inhibitory avoidance learning task. Repeated treatment with 1 mg/kg/day methyl parathion resulted in a 50% inhibition of blood cholinesterase activity. A decrease in locomotor activity and impairment of memory were also observed after 28 days of repeated treatment. Thus, a single dermal exposure of rats to doses of methyl parathion which are lower than those that elicit acute toxicity can cause decrements in both cholinesterase activity and motor function which are reversible. In contrast, repeated low-dose dermal treatment results in a sustained inhibition of cholinesterase activity and impairment of both motor function and memory.
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Anonymous: Methyl parathion comes inside. Environ Health Perspect 105:690–691;1997.
Bakin JS, Weinberger NM. Induction of a physiological memory in the cerebral cortex by stimulation of the nucleus basalis. Proc Natl Acad Sci USA 93:11219–11224;1996.
Baskerville KA, Schweitzer JB, Herron P. Effects of cholinergic depletion on experience-dependent plasticity in the cortex of the rat. Neuroscience 80:1159–1169;1997.
Benke GM, Murphy SD. Anticholinesterase action of methyl parathion, parathion and azinphosmethyl in mice and fish: Onset and recovery of inhibition. Bull Environ Contam Toxicol 12:117–122;1974.
Blaber JC, Creasey NH. The mode of recovery of cholinesterase activity in vivo after organophosphorus poisoning: 1. Erythrocyte cholinesterase. Biochem J 77:591–596;1960.
Blaber JC, Creasey NH. The mode of recovery of cholinesterase activity in vivo after organophosphorus poisoning: 2. Brain cholinesterase. Biochem J 77:597–604;1960.
Bushnell PJ, Kelly KL, Ward TR. Repeated inhibition of cholinesterase by chlorpyrifos in rats: Behavioral, neurochemical and pharmacological indices of tolerance. J Pharmacol Exp Ther 271:15–25;1994.
Bushnell PJ, Padilla SS, Ward TR, Pope CN, Olszyk VB. Behavioral and neurochemical changes in rats dosed repeatedly with diisopropylfluorophosphate. J Pharmacol Exp Ther 256:741–750;1991.
Carr RL, Chambers JE. Acute effects of the organophosphate paraoxon on schedule-controlled behavior and esterase activity in rats: Dose-response relationships. Pharmacol Biochem Behav 40:929–936;1991.
Carriero DL, Outslay G, Mayorga AJ, Aberman J, Gianutsos G, Salamone JD. Motor dysfunction produced by tacrine administration in rats. Pharmacol Biochem Behav 58:851–858;1997.
Chaudhuri J, Chakraborti TK, Chanda S, Pope CN. Differential modulation of organophosphate-sensitive muscarinic receptors in rat brain by parathion and chlorpyrifos. J Biochem Toxicol 8:207–216;1993.
Clifford NJ, Nies AS. Organophosphate poisoning from wearing a laundered uniform previously contaminated with parathion. JAMA 262:3035–3036;1989.
Crisson CM, Wilson BW. Recovery of acetylcholinesterase in cultured chick embryo muscle treated with paraoxon. Biochem Pharmacol 26:1955–1960;1977.
D'Mello GD. Behavioral toxicity of anticholinesterases in humans and animals — a review. Hum Exp Toxicol 12:3–7;1993.
Durham WF, Wolfe HR, Elliot JW. Absorption and excretion of parathion by spraymen. Arch Environ Health 24:381–387;1972.
Ellman GC, Courtney KO, Andres V, Featherstone RM. A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem Pharmacol 7:88–95;1961.
Environmental Protection Agency: Illegal Indoor Use of Methyl Parathion 2000.
Gaines TB. The acute toxicology of pesticides to rats. Toxicol Appl Pharmacol 2:88–99;1960.
George J, Andrade C, Joseph T. Delayed effects of acute oral and chronic inhalational exposure to methyl parathion on learning and memory in rats. Indian J Exp Biol 30:819–822;1992.
Gupta RC, Rech RH, Lovell KL, Welsch F, Thornburg JE. Brain cholinergic, behavioral, and morphological development in rats exposed in utero to methyl parathion. Toxicol Appl Pharmacol 77:405–413;1985.
Hobbiger FW. Effect of nicotinhydroxamic acid methiodide on human plasma cholinesterase inhibited by organophosphates containing a dialkylphosphate group. Br J Pharmacol 10:356–362;1955.
Le Couteur DG, McLean AJ, Taylor MC, Woodham BL, Board PG. Pesticides and Parkinson's disease. Biomed Pharmacother 53:122–130;1999.
Levin HL, Rodnitzky LR. Behavioral effects of organophosphate pesticides in man. Clin Toxicol 9:391–405;1976.
Llorens J, Crofton KM, Tilson HA, Ali SF, Mundy WR. Characterization of disulfoton-induced behavioral and neurochemical effects following repeated exposure. Fundam Appl Toxicol 20:163–169;1993.
Matsumura F: Toxicology of Insecticides, ed 2. New York, Plenum, 497–498;1985.
McDonald BE, Costa LG, Murphy SD. Spatial memory impairment and central muscarinic receptor loss following prolonged treatment with organophosphates. Toxicol Lett 40:47–56;1988.
Midtling JE, Barnett PG, Coye MJ, Velasco AR, Romero P, Clements CL, O'Malley MA, Tobin MW, Rose TG, Monosson IH. Clinical management of field worker organophosphate poisoning. West J Med 142:514–518;1985.
Nagymajtenyi L, Desi I, Lorencz R. Neurophysiological markers as early signs of organophosphate neurotoxicity. Neurotoxicol Teratol 10:4429–4434;1988.
Nemec SJ, Adkisson PL, Dorough HW. Methyl parathion absorbed on the skin and blood cholinesterase levels of persons checking cotton treated with ultra-low-volume sprays. J Econ Entomol 61:1740–1742;1968.
Noring U, Povlsen UJ, Casey DE, Gerlach J. Effect of a cholinomimetic drug (RS 86) in tardive dyskinesia and drug-related parkinsonism. Psychopharmacology (Berl) 84:569–571;1984.
Nostrandt AC, Duncan JA, Padilla S. A modified spectrophotometric method appropriate for measuring cholinesterase activity in tissue from carbaryl-treated animals. Fundam Appl Toxicol 21:196–203;1993.
Ott BR, Lannon MC. Exacerbation of parkinsonism by tacrine. Clin Neuropharmacol 15:322–325;1992.
Overstreet DH. Behavioral plasticity and the cholinergic system. Prog Neuropsychopharmacol Biol Psychiatry 8:133–151;1984.
Pope CN, Chakraborti TK, Chapman ML, Farrar JD, Arthun D. comparison of in vivo cholinesterase inhibition in neonatal and adult rats by three organophosphorothioate insecticides. Toxicology 68:51–61;1991.
Reiner E. Spontaneous reactivation of phosphorylated and carbamylated cholinesterases. Bull World Health Organ 44:109–112;1971.
Romano JA Jr, Landauer MR. Effects of the organophosphorus compound, O-ethyl-N-dimethyl-phosphoramidocyanidate (tabun), on flavor aversions, locomotor activity, and rotarod performance in rats. Fundam Appl Toxicol 6:62–68;1986.
Sachdev R, Lu S, Wiley R, Ebner F. Role of the basal forebrain cholinergic projection in somatosensory cortical plasticity. J Neurophysiol 79:3216–3228;1998.
Simpson GR. Exposure to orchard pesticides. Dermal and inhalation exposures. Arch Environ Health 10:884–885;1965.
Tafuri J, Roberts J. Organophosphate poisoning. Ann Emerg Med 16:193–202;1987.
Taylor P. Anticholinesterase agents. In: Hardman JG, Limbird LE, Molinoff PB, Ruddon RW, Gilman AG, eds. Goodman and Gillman's The Pharmacological Basis of Therapeutics, ed 9. New York, McGraw-Hill, 177–197;1996.
van Kampen EJ, Zijlstra WG. Spectrophotometry of hemoglobin and hemoglobin derivatives. Adv Clin Chem 23:199–255;1983.
Ware GW, Morgan DP, Estesen BJ, Cahill WP. Establishment of reentry intervals for organophosphate-treated cotton fields based on human data. I. Ethyl and methyl parathion. Arch Environ Contam Toxicol 1:48–49;1973.
Ware GW, Morgan DP, Estesen BJ, Cahill WP. Establishment of reentry intervals for organophosphate-treated cotton fields based on human data. III. 12 to 17 hours post-treatment exposure to monocrotophos, ethyl and methyl parathion. Arch Environ Contam Toxicol 3:289–306;1975.
Youssef SHA, El-Sayed MGA, Atef M. Influence of gentamicin and rifamycin on toxicity and biotransformation of methyl parathione in rats. Dtsch Tierärztl Wochenschr 94:203–205;1987.
Zhu XO, Waite PME. Cholinergic depletion reduces plasticity of barrel field cortex. Cereb Cortex 8:63–72;1998.
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Zhu, H., Rockhold, R.W., Baker, R.C. et al. Effects of single or repeated dermal exposure to methyl parathion on behavior and blood cholinesterase activity in rats. J Biomed Sci 8, 467–474 (2001). https://doi.org/10.1007/BF02256609
- Methyl parathion
- Dermal exposure
- Motor function