Tags

Type your tag names separated by a space and hit enter

Comparative in vivo effects of parathion on striatal acetylcholine accumulation in adult and aged rats.
Toxicology. 2007 Oct 08; 239(3):167-79.T

Abstract

Aged rats are more sensitive to the acute toxicity of the prototype organophosphate insecticide, parathion. We compared the acute effects of parathion on diaphragm and brain regional cholinesterase activity, muscarinic receptor binding and striatal acetylcholine levels in 3- and 18-month-old male Sprague-Dawley rats. Adult and aged rats were surgically implanted with a microdialysis cannula into the right striatum 5-7 days prior to parathion treatment. Rats were given either vehicle (peanut oil, 2 ml/kg) or one of a range of dosages of parathion (adult: 1.8, 3.4, 6.0, 9.0, 18 and 27 mg/kg, s.c.; aged: 1.8, 3.4, 6 and 9 mg/kg, s.c.) and body weight, functional signs of toxicity, and nocturnal motor activity were recorded for seven days. Three and seven days after parathion treatment, microdialysis samples were collected and rats were subsequently sacrificed for biochemical measurements. Higher dosages of parathion led to significant time-dependent reductions in body weight in both age groups. Rats in both age groups treated with lower dosages showed few overt signs of cholinergic toxicity while equitoxic high dosages (adult, 27 mg/kg; aged, 9 mg/kg) elicited marked signs of cholinergic toxicity (involuntary movements and SLUD [i.e., acronym for Salivation, Lacrimation, Urination and Defecation] signs) with peak effects being noted 3-4 days after treatment. Nocturnal activity (ambulation and rearing) was reduced in both age groups following parathion dosing, with more prominent effects in adults and rearing being more consistently affected. Dose- and time-dependent inhibition of cholinesterase activity was noted in both diaphragm and striatum. Total muscarinic receptor ([(3)H]quinuclidinyl benzilate, QNB) binding was significantly lower in aged rats, and both total binding and muscarinic agonist ([(3)H]oxotremorine methiodide] binding was significantly reduced in both age-groups treated with the highest dosages of parathion (adult, 27 mg/kg; aged, 9 mg/kg). In contrast to relatively similar levels of cholinesterase inhibition, striatal extracellular acetylcholine levels were significantly lower (2.2- to 2.9-fold) in aged rats at both 3 and 7 day time-points compared to adult rats treated with equitoxic dosages (i.e., 9 and 27 mg/kg, respectively). No age-related differences in in vitro striatal acetylcholine synthesis or in vivo acetylcholine accumulation following direct infusion of the cholinesterase inhibitor neostigmine (1 microM) were noted. While aged rats are more sensitive than adults to the acute toxicity of parathion, lesser acetylcholine accumulation was noted in the striatum of aged rats exhibiting similar levels of cholinesterase inhibition. These findings suggest that lesser acetylcholine accumulation may be required to elicit cholinergic signs in the aged rat, possibly based on aging-associated changes in muscarinic receptor density.

Authors+Show Affiliations

Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, United States.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17707571

Citation

Karanth, Subramanya, et al. "Comparative in Vivo Effects of Parathion On Striatal Acetylcholine Accumulation in Adult and Aged Rats." Toxicology, vol. 239, no. 3, 2007, pp. 167-79.
Karanth S, Liu J, Ray A, et al. Comparative in vivo effects of parathion on striatal acetylcholine accumulation in adult and aged rats. Toxicology. 2007;239(3):167-79.
Karanth, S., Liu, J., Ray, A., & Pope, C. (2007). Comparative in vivo effects of parathion on striatal acetylcholine accumulation in adult and aged rats. Toxicology, 239(3), 167-79.
Karanth S, et al. Comparative in Vivo Effects of Parathion On Striatal Acetylcholine Accumulation in Adult and Aged Rats. Toxicology. 2007 Oct 8;239(3):167-79. PubMed PMID: 17707571.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparative in vivo effects of parathion on striatal acetylcholine accumulation in adult and aged rats. AU - Karanth,Subramanya, AU - Liu,Jing, AU - Ray,Anamika, AU - Pope,Carey, Y1 - 2007/07/13/ PY - 2007/03/07/received PY - 2007/07/03/revised PY - 2007/07/05/accepted PY - 2007/8/21/pubmed PY - 2007/11/10/medline PY - 2007/8/21/entrez SP - 167 EP - 79 JF - Toxicology JO - Toxicology VL - 239 IS - 3 N2 - Aged rats are more sensitive to the acute toxicity of the prototype organophosphate insecticide, parathion. We compared the acute effects of parathion on diaphragm and brain regional cholinesterase activity, muscarinic receptor binding and striatal acetylcholine levels in 3- and 18-month-old male Sprague-Dawley rats. Adult and aged rats were surgically implanted with a microdialysis cannula into the right striatum 5-7 days prior to parathion treatment. Rats were given either vehicle (peanut oil, 2 ml/kg) or one of a range of dosages of parathion (adult: 1.8, 3.4, 6.0, 9.0, 18 and 27 mg/kg, s.c.; aged: 1.8, 3.4, 6 and 9 mg/kg, s.c.) and body weight, functional signs of toxicity, and nocturnal motor activity were recorded for seven days. Three and seven days after parathion treatment, microdialysis samples were collected and rats were subsequently sacrificed for biochemical measurements. Higher dosages of parathion led to significant time-dependent reductions in body weight in both age groups. Rats in both age groups treated with lower dosages showed few overt signs of cholinergic toxicity while equitoxic high dosages (adult, 27 mg/kg; aged, 9 mg/kg) elicited marked signs of cholinergic toxicity (involuntary movements and SLUD [i.e., acronym for Salivation, Lacrimation, Urination and Defecation] signs) with peak effects being noted 3-4 days after treatment. Nocturnal activity (ambulation and rearing) was reduced in both age groups following parathion dosing, with more prominent effects in adults and rearing being more consistently affected. Dose- and time-dependent inhibition of cholinesterase activity was noted in both diaphragm and striatum. Total muscarinic receptor ([(3)H]quinuclidinyl benzilate, QNB) binding was significantly lower in aged rats, and both total binding and muscarinic agonist ([(3)H]oxotremorine methiodide] binding was significantly reduced in both age-groups treated with the highest dosages of parathion (adult, 27 mg/kg; aged, 9 mg/kg). In contrast to relatively similar levels of cholinesterase inhibition, striatal extracellular acetylcholine levels were significantly lower (2.2- to 2.9-fold) in aged rats at both 3 and 7 day time-points compared to adult rats treated with equitoxic dosages (i.e., 9 and 27 mg/kg, respectively). No age-related differences in in vitro striatal acetylcholine synthesis or in vivo acetylcholine accumulation following direct infusion of the cholinesterase inhibitor neostigmine (1 microM) were noted. While aged rats are more sensitive than adults to the acute toxicity of parathion, lesser acetylcholine accumulation was noted in the striatum of aged rats exhibiting similar levels of cholinesterase inhibition. These findings suggest that lesser acetylcholine accumulation may be required to elicit cholinergic signs in the aged rat, possibly based on aging-associated changes in muscarinic receptor density. SN - 0300-483X UR - https://www.unboundmedicine.com/medline/citation/17707571/Comparative_in_vivo_effects_of_parathion_on_striatal_acetylcholine_accumulation_in_adult_and_aged_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0300-483X(07)00457-X DB - PRIME DP - Unbound Medicine ER -