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Khan HA. N-nitro-L-arginine, a nitric oxide synthase inhibitor, aggravates iminodipropionitrile-induced neurobehavioral and vestibular toxicities in rats. EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY : OFFICIAL JOURNAL OF THE GESELLSCHAFT FUR TOXIKOLOGISCHE PATHOLOGIE 2012; 64:791-6. [PMID: 21388795 DOI: 10.1016/j.etp.2011.01.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Revised: 01/12/2011] [Accepted: 01/30/2011] [Indexed: 02/08/2023]
Abstract
Exposure of iminodipropionitrile (IDPN) to rodents produces permanent behavioral syndrome characterized by repetitive head movements, circling and back walking. Other synthetic nitriles of industrial importance such as crotonitrile and allylnitrile are also able to produce similar motor deficits in experimental animals. However, due to the well-defined behavioral deficits and their easy quantification, IDPN-induced behavioral syndrome is a preferential animal model to test the interaction of various agents with synthetic nitriles. This study reports the effect of non-specific nitric oxide synthase inhibitor, N-nitro-L-arginine (NARG) on IDPN-induced neurobehavioral toxicity in adult male Wistar rats. Four groups of animals were given i.p. injections of IDPN (100 mg/kg) for 6 days. These rats were treated with oral administration of NARG in the doses of 0 (IDPN alone group), 50, 150 and 300 mg/kg, 60 min before IDPN, respectively. Control rats received vehicle only, whereas another group was treated with 300 mg/kg of NARG alone (without IDPN). The results showed that NARG significantly exacerbated the incidence and intensity of IDPN-induced dyskinetic head movements, circling and back walking. The histology of inner ear showed massive degeneration of the sensory hair cells in the crista ampullaris of rats receiving the combined treatment with IDPN and NARG, suggesting a possible role of nitric oxide in IDPN-induced neurobehavioral syndrome in rats.
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Affiliation(s)
- Haseeb Ahmad Khan
- Analytical and Molecular Bioscience Research Group, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
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Wonodi I, Gopinath HV, Liu J, Adami H, Hong LE, Allen-Emerson R, McMahon RP, Thaker GK. Dipyridamole monotherapy in schizophrenia: pilot of a novel treatment approach by modulation of purinergic signaling. Psychopharmacology (Berl) 2011; 218:341-5. [PMID: 21537940 PMCID: PMC4009981 DOI: 10.1007/s00213-011-2315-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 04/15/2011] [Indexed: 01/24/2023]
Abstract
BACKGROUND Emerging data indicate the neuromodulator adenosine may play a role in the therapeutics of schizophrenia. Adenosine A(2A) receptor stimulation exerts a functional antagonism at postsynaptic D(2) receptors. Data from animal models relevant to schizophrenia support a therapeutic effect of modulating adenosinergic transmission in the ventral striatum. One previous clinical trial showed superiority of adjunctive dipyridamole, an adenosine reuptake inhibitor, compared to placebo in ameliorating positive symptoms in schizophrenia patients. OBJECTIVES The aim of this study was to examine the effects of dipyridamole monotherapy of 200 mg/day on positive and negative symptoms, with the goal of determining dosing for future adjunctive studies in schizophrenia. METHODS Twenty symptomatic schizophrenia participants were randomized to a 6-week double-blind trial comparing olanzapine (20 mg/day) to dipyridamole monotherapy (200 mg/day). Thirteen participants completed the treatment phase (eight on dipyridamole; five on olanzapine). RESULTS The olanzapine group showed a trend (p = 0.08) for superiority on BPRS total scores (mean ± SD: total BPRS score decreasing from 36.8 ± 2.3 at week 1, to 33.2 ± 5.5 at the end of the study). The mean total BPRS scores decreased from 36.4 ± 5.3 to 34.0 ± 7.7 in the dipyridamole group. CONCLUSIONS Although these pilot data do not support a significant antipsychotic effect of dipyridamole monotherapy, the results provide some evidence for examining dipyridamole (200 mg/day) as adjunct to symptomatic antipsychotic-treated schizophrenia patients.
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Affiliation(s)
- Ikwunga Wonodi
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA.
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Tariq M, Khan HA, Siddiquei MM, Al Moutaery K, Al Deeb S. Protective effect of hydrocortisone on iminodipropionitrile-induced neurotoxicity in rats. Basic Clin Pharmacol Toxicol 2007; 100:176-81. [PMID: 17309521 DOI: 10.1111/j.1742-7843.2006.00037.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Occupational and environmental exposure of synthetic nitriles is of potential relevance to human health. Iminodipropionitrile (IDPN), a prototype nitrile toxin, has been shown to produce dyskinetic syndrome in rodents. This study reports the effect of concomitant exposure of rats to hydrocortisone and IDPN on behavioural abnormalities namely excitation, circling and chorea (ECC) syndrome. Four groups of female Wistar rats were given hydrocortisone (0, 10, 30 and 60 mg/kg, gavage, for 10 days) 30 min. before IDPN (100 mg/kg, intraperitoneally for 8 days). Two additional groups of rats were treated with either saline (control group) or 60 mg/kg of hydrocortisone (drug alone group). The animals were observed for neurobehavioural abnormalities including dyskinetic head movement, circling, tail hanging, air righting reflex and contact inhibition of righting reflex. After behavioural studies, the animals were killed, and the discrete brain regions and temporal bones were collected for biochemistry and inner ear histopathology, respectively. Hydrocortisone significantly and dose dependently attenuated the incidence and severity of IDPN-induced behavioural syndrome. Administration of hydrocortisone (60 mg/kg) alone significantly increased glutathione (GSH) levels in olfactory bulb and striatum, whereas IDPN alone significantly reduced GSH levels in olfactory bulb, striatum and hippocampus. Hydrocortisone (60 mg/kg) significantly compensated IDPN-induced depletions of GSH in different brain regions. Hydrocortisone also protected the animals against IDPN-induced vestibular hair cell degeneration. The protective effect of hydrocortisone may be attributed to its anti-inflammatory and antioxidant properties.
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Affiliation(s)
- Mohammad Tariq
- Neuroscience Research Group, Armed Forces Hospital, Riyadh, Saudi Arabia.
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Ahmad Khan H, Al Deeb S, Al Moutaery K, Tariq M. Metoclopramide attenuates iminodipropionitrile-induced oxidative stress and neurobehavioral toxicity in rats. Pharmacol Biochem Behav 2004; 79:555-61. [PMID: 15582028 DOI: 10.1016/j.pbb.2004.09.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Revised: 08/23/2004] [Accepted: 09/07/2004] [Indexed: 02/08/2023]
Abstract
Metoclopramide (MET) has long been used as a neuroleptic and antiemetic drug in clinical practice. Motor impairment and dyskinesia have been reported in some patients following chronic treatment with MET. Occasionally, the adverse symptoms may appear even after acute exposure to MET in more susceptible population (such as elderly individual) or due to concomitant exposure to MET and certain neurotoxins. Iminodipropionitrile (IDPN), a prototype nitrile toxin, has been shown to produce dyskinetic syndrome in rodents. This study reports the effect of concomitant exposure of rats to MET and IDPN on behavioral abnormalities in rats namely excitation, circling and chorea (ECC) syndrome. Four groups of female Wistar rats (aged 3 months) were given MET (0, 10, 40 and 80 mg/kg, i.p., for 11 days) 30 min before IDPN (100 mg/kg, i.p. for 8 days). Two additional groups of rats were treated with either saline (control group) or 80 mg/kg of MET (drug alone group). The animals were observed for neurobehavioral abnormalities including dyskinetic head movement, circling, tail hanging, air righting reflex and contact inhibition of righting reflex. Horizontal and vertical locomotor activities and fore limbs grip strength were also measured. On day 12, the animals were sacrificed and brains were collected for biochemical analysis. MET significantly and dose-dependently protected the animals against IDPN-induced ECC syndrome, motor impairment and deficiency in grip strength. MET also protected the animals against IDPN-induced oxidative stress.
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Affiliation(s)
- Haseeb Ahmad Khan
- Neuroscience Research Group, Armed Forces Hospital, P.O. Box 7897 (W-912), Riyadh 11159, Kingdom of Saudi Arabia
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Tariq M, Khan HA, Al Deeb S, Al Moutaery K. Nitric oxide synthase inhibitor aminoguanidine potentiates iminodipropionitrile-induced neurotoxicity in rats. Neurosci Lett 1999; 276:49-52. [PMID: 10586972 DOI: 10.1016/s0304-3940(99)00789-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This investigation was undertaken to study the effect of nitric oxide synthase inhibitor, aminoguanidine on iminodipropionitrile (IDPN)-induced neurobehavioral and vestibular toxicity in rats. The dyskinetic syndrome was produced in male Wistar rats by i.p. injections of IDPN (100 mg/kg) for 6 days. Aminoguanidine was administered orally in the doses of 50, 150 and 300 mg/kg, 60 min before IDPN in three different groups. Control rats received vehicle only, whereas another group was treated with 300 mg/kg of aminoguanidine alone (without IDPN). Our results showed that aminoguanidine significantly and dose dependently exacerbated the incidence and intensity of IDPN-induced dyskinetic head movements. Aminoguanidine potentiated IDPN-induced loss of air righting reflex. The histopathological examination of inner ear showed aggravation of IDPN-induced degeneration of sensory hair cells in the crista ampullaris by aminoguanidine. These results suggest the role of nitric oxide in IDPN-induced neurobehavioral and vestibular toxicity.
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Affiliation(s)
- M Tariq
- Neuroscience Research Group, Armed Forces Hospital, Riyadh, Saudi Arabia
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Tariq M, Khan HA, al Moutaery K, al Deeb S. Protection by 2-deoxy-D-glucose against beta,beta'-iminodipropionitrile-induced neurobehavioral toxicity in mice. Exp Neurol 1999; 158:229-33. [PMID: 10448436 DOI: 10.1006/exnr.1999.7103] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This investigation was undertaken to study the effect of 2-deoxy-D-glucose (2-DG) on beta, beta'-iminodipropionitrile (IDPN)-induced neurobehavioral toxicity in mice. Animals were divided into five groups of nine animals each. One of the groups served as control and received vehicle only, whereas the remaining four groups were treated with IDPN (250 mg/kg, i.p.) daily for 11 days. 2-DG was injected intraperitoneally in the doses of 0 (vehicle only), 100, 300, and 600 mg/kg daily 30 min before IDPN administration. The animals were observed for dyskinetic behavior including vertical (retrocollis) and horizontal (laterocollis) head movements and circling. Twenty-four hours after the last dose of IDPN, the animals were sacrificed by decapitation and striata were isolated from the brain for the analysis of serotonin (5-HT). Our results showed that 2-DG significantly and dose dependently attenuated the incidence and severity of IDPN-induced neurobehavioral toxicity. Administration of 2-DG also protected mice against IDPN-induced increase in striatal 5-HT levels. Further studies are warranted to investigate the neuroprotective mechanism of 2-DG against IDPN-induced neurotoxicity.
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Affiliation(s)
- M Tariq
- Neuroscience Research Group, Armed Forces Hospital, Riyadh, Saudi Arabia
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Tariq M, Khan HA, Moutaery KA, Deeb SA. Tolerance to beta,beta'-iminodipropionitrile (IDPN)-induced neurobehavioural and vestibular toxicity in diabetic rats. J Appl Toxicol 1999; 19:93-9. [PMID: 10215181 DOI: 10.1002/(sici)1099-1263(199903/04)19:2<93::aid-jat547>3.0.co;2-f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The present investigation was undertaken to study the neurotoxic effects of beta,beta'-iminodipropionitrile (IDPN) in normal, diabetic and insulin-treated diabetic rats. Sprague-Dawley male rats were divided into five groups: control, IDPN, diabetes, diabetes plus IDPN and diabetes plus insulin plus IDPN. The diabetes was induced with a single i.p. injection of streptozotocin (50 mg kg(-1)). One month after the induction of diabetes, the rats were treated with IDPN (100 mg kg(-1), i.p.) daily for 11 days. One of the diabetic groups treated with IDPN also received daily injection of insulin (25 U kg(-1), s.c.), 1 h before IDPN. The rats were observed daily for abnormal head movements and circling. The grip strength of the forelimbs was also measured. In the IDPN group the dyskinetic symptoms appeared on the 8th day, whereas the onset of dyskinesia was on the 12th day in IDPN-treated diabetic rats. The incidence and severity of dyskinesia were significantly higher in IDPN-treated normal (non-diabetic) rats as compared to IDPN-treated diabetic rats. The treatment of diabetic rats with insulin normalized striatal dopamine (DA) turnover but partially reversed diabetes-induced protection against IDPN dyskinesia. There was severe degeneration of sensory hair cells in crista ampullaris of IDPN-treated normal rats, whereas the diabetic rats showed significant protection against IDPN-induced vestibular hair cell degeneration. In conclusion, our study clearly demonstrates that diabetic rats are resistant to IDPN-induced neurobehavioural and vestibular toxicity. The results also show that diabetes-induced protection against IDPN-induced dyskinesia can be partially reversed by insulin. The mechanism behind the decreased vulnerability of diabetic animals to IDPN remains to be resolved. Further studies are warranted to investigate this paradoxical phenomenon.
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MESH Headings
- 3,4-Dihydroxyphenylacetic Acid/metabolism
- Animals
- Behavior, Animal/drug effects
- Blood Glucose
- Body Weight
- Brain/drug effects
- Brain/metabolism
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Dopamine/metabolism
- Dyskinesia, Drug-Induced/etiology
- Dyskinesia, Drug-Induced/metabolism
- Dyskinesia, Drug-Induced/prevention & control
- Insulin/therapeutic use
- Male
- Neurotoxins/toxicity
- Nitriles/toxicity
- Rats
- Rats, Sprague-Dawley
- Vestibule, Labyrinth/drug effects
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Affiliation(s)
- M Tariq
- Neuroscience Research Group, Armed Forces Hospital, Riyadh, Saudi Arabia
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Tariq M, Khan HA, Rehana Z, Al Moutaery K, Al Deeb S. Proglumide, a cholecystokinin receptor antagonist, exacerbates beta, beta'-iminodipropionitrile-induced dyskinetic syndrome in rats. Neurotoxicol Teratol 1998; 20:571-9. [PMID: 9761597 DOI: 10.1016/s0892-0362(98)00019-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The present investigation was undertaken to study the effect of proglumide, a cholecystokinin (CCK) receptor antagonist, on iminodipropionitrile (IDPN)-induced excitation, chorea, and circling (ECC) syndrome in rats. The animals were exposed to IDPN in the dose of 100 mg/kg/day IP for 9 days. Proglumide (PG) was administered IP daily 1 h before IDPN in the doses of 250, 500, and 750 mg/kg body weight in three different groups of rats. The animals were observed daily for neurobehavioral abnormalities including dyskinetic head movements, circling, tail hanging, air righting reflex, locomotor activity, and contact inhibition of the righting reflex. After behavioral studies, blood and brain samples were collected for the analysis of malondialdehyde (MDA), conjugated dienes, vitamin E, and glutathione peroxidase (GSH-Px). The temporal bones were also collected for inner ear histopathology. Our results showed that proglumide significantly and dose-dependently exacerbated the incidence and the severity of IDPN-induced ECC syndrome during the treatment period as well as up to 3 weeks of postdosing. Administration of IDPN produced a significant increase in MDA and conjugated dienes and a decrease in vitamin E and GSH-Px, suggesting the role of oxygen-derived free radicals (ODFR) in IDPN-induced neurotoxicity. Concomitant treatment with proglumide potentiated IDPN-induced oxidative stress. The histopathology of the inner ear showed significantly high degeneration of sensory hair cells in the crista ampullaris of the rats treated with IDPN plus proglumide compared to IDPN-alone-treated animals. Further studies are warranted to determine the role of CCK in nitrile toxicity and drug-induced dyskinesia.
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Affiliation(s)
- M Tariq
- Neuroscience Research Group, Armed Forces Hospital, Riyadh, Saudi Arabia
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Dipyridamole potentiates 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced experimental Parkinsonism in mice. Parkinsonism Relat Disord 1998; 4:43-50. [DOI: 10.1016/s1353-8020(98)00007-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Abstract
Iminodipropionitrile (IDPN), a compound that causes dyskinetic symptoms in animals and has possible use as a model for human dyskinesia, was tested in mice and rats for its effect on cerebral amino acids. In mice, 2 h after IDPN administration, the level of total brain alanine was reduced; after 5 h the levels of aspartic acid and glutamic acid were also reduced, and the level of glutamine was increased. In rats, after chronic administration of IDPN, the level of glutamic acid in the total brain tissue was reduced. After acute administration of IDPN using microdialysis, extracellular GABA and extracellular glutamine levels in the striatum were elevated. This study shows that IDPN causes alterations in total and extracellular levels of neurotransmitter amino acids in the brain, which could have a role in IDPN-induced dyskinesia.
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Affiliation(s)
- E Toth
- The Nathan S. Kline Institute for Psychiatric Research, Center for Neurochemistry, Orangeburg, NY 10962, USA
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