Learning impairment

Paul V, Balasubramaniam E, Kazi M. 1994. The neurobehavioural toxicity of endosulfan in rats a serotonergic involvement in learning impairment. Eur J Pharmacol 270(1) 1-7. 

Nitta, A, Fukuta, T, Hasegawa, T and Nabeshima, T (1997) Continuous infusion of -amyloid proteins into cerebral ventricle induces learning impairment and neuronal and morphological degeneration. Jpn J. Pharmacol. 73 51-57. 

Lione LA, Carter RJ, Hunt MJ, Bates GP, Morton AJ, Dunnett SB. Selective discrimination learning impairments in mice expressing the human Huntington s disease mutation. J Neurosci 1999 19 10428— 10437. 

Cory-Slechta DA. 1995a. Relationships between lead-induced learning impairments and changes in dopaminergic, cholinergic, and glutamatergic neurotransmitter system functions. Annu Rev Pharmacol Toxicol 35 391-415. 

Squirrel monkey, Saimiri spp. fetuses, 80-90 days postconception given 0.1 or 1.0 Gy, single acute exposure young observed from birth to age 2 years No effect on behavior at 0.1 Gy. At 1 Gy, emotional stability and vision impaired at age 30 days, learning impaired at 1 year normal at 2 years 44... 

Nishiyama N, Wang YL, Saito H. (1995). Beneficial effects of S-113m, a novel herbal prescription, on learning impairment model in mice. Biol Pharm Bull. 18(11) 1498-503. 

Several recent epidemiological studies have involved examination of populations that consume unusually high levels of fish. One of these, conducted in the islands of the Seychelles, has not so far revealed behavioral and learning impairments in children whose mothers exhibited mercury levels (measured in hair) higher than those typically seen in the United States and European countries. But another study, conducted in the Faroe Islands, turned up evidence of cognitive and behavioral impairments in children. Scientists have struggled to understand why two well-done studies have produced such different outcomes, and some possible reasons have been suggested. The EPA and public health officials have acted on the basis of the Faroe data, out of both caution and also because they seem to be supported by other, more limited data, and by experimental studies. The debate is not so much about whether methylmercury is a developmental toxicant, but rather over the dose required. 

Memory problems, confusion, speech impairment, learning impairment... 

Paul lA, Layer RT, Skolnick P, et al Adaptation of the N-methyl-D-aspartate receptor complex in rat front cortex following chronic treatment with electroconvulsive shock or imipramine. Eur J Pharmacol 247 305-312, 1993 Paul SM, Purdy RH Neuroactive steroids. FASEB J 6 2311-2322, 1992 Paul V, Balasubramaniam E, Kazi M The neurobehavioural toxicity of endosulfan in rats a serotonergic involvement in learning impairment. Eur J Pharmacol 270 1-7, 1994... 

Nishiyama, N., H. Saito, and P. J. Chu. 1995. Beneficial effects of biota, a traditional Chinese herbal medicine, on learning impairment induced by basal forebrain-lesion in mice. Biol. Pharm. Bull. 18 1513-1517. 

Gage, F.H., Bjorklund, A., Stenevi, U., Dunnett, S.B., Kelly, P.A. (1984). Intrahippocampal septal grafts ameliorate learning impairments in aged rats. Science, 225, 533-6. 

Nicolle M. M., Colombo P. J., Gallagher M., and McKinney M. (1999). Metabotropic glutamate receptor-mediated hippocampal phosphoinositide turnover is blunted in spatial learning-impaired aged rats. J. Neurosci. 19 9604-9610. 

Another study showed ecstasy users to have decreased blood flow to the brain (thought to be regulated by serotonin), and that the reduction in blood flow depended on dose, meaning there was a greater decrease among participants who had used ecstasy more often. Similarly, memory and learning impairment was more profound among people who had used ecstasy more often. 

Experiments and data presented in this chapter demonstrate that delta opioid agonists have antidepressant-like effects in animal models used to measure antidepressant activity. The antidepressant-like effects can be separated from other behavioral effects produced by these compounds, such as locomotor stimulation, convulsions, and learning impairments. This separation lends validity to this potential target for depression by eliminating effects or sources that may produce false positives. These compounds should be tested in other models of antidepressant activity to confirm these findings in the forced swim test. 

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