thiourea and Learning-Disabilities

Obstructive sleep apnea hypopnea syndrome (OSAHS) in children is associated with multiple system morbidities. Cognitive dysfunction as a result of central nervous system complication has been reported in children with OSAHS. However, the underlying mechanisms are poorly understood. Endoplasmic reticulum stress (ERS)-related apoptosis plays an important role in various diseases of the central nervous system, but very little is known about the role of ERS in mediating pathophysiological reactions to cognitive dysfunction in OSAHS. Chronic intermittent hypoxia (CIH) exposures, modeling OSAHS, across 2 and 4weeks in growing rats made more reference memory errors, working memory errors and total memory errors in the 8-Arm radial maze task, increased significantly TUNEL positive cells, upregulated the unfolded protein response in the hippocampus and prefrontal cortex as evidenced by increased phosphorylation of PKR-like endoplasmic reticulum kinase, inositol-requiring enzyme l and some downstream products. A selective inhibitor of eukaryotic initiation factor-2a dephosphorylation, salubrinal, prevented C/EBP-homologous protein activation in the hippocampus and prefrontal cortex throughout hypoxia/reoxygenation exposure. Our findings suggest that ERS mediated cell apoptosis may be one of the underlying mechanisms of cognitive dysfunction in OSAHS children. Further, a specific ERS inhibitor Salubrinal should be tested for neuroprotection against CIH-induced injury.

Topics: Age Factors; Aging; Animals; Blood Pressure; Brain Injuries; Cinnamates; Disease Models, Animal; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Hippocampus; Hypoxia; Learning Disabilities; Male; Maze Learning; Oligopeptides; Prefrontal Cortex; Rats; Rats, Sprague-Dawley; Thiourea; Time Factors; Transcription Factors

Schizophrenia (SCZ) afflicts around 1% of the world's population with characteristic symptoms such as hallucinations, delusions, and cognitive disorders. Several experimental studies in the past have indicted brain histaminergic neuronal system involvement in the pathogenesis of psychotic disorders including SCZ. Present study investigates anti-schizophrenic activity using two histamine H(3)-receptor (H(3)R)-antagonists/inverse agonists, ciproxifan (3.0 mg/kg, i.p.) and clobenpropit (15 mg/kg, i.p.), on some of the established animal model of schizophrenia, for example, amphetamine (AMPH) and dizocilpine (MK-801)-induced hyperactivity, apomorphine (APO)-induced climbing behavior, scopolamine and MK-801-induced learning and memory deficits and haloperidol-induced catalepsy including determination of acetylcholinesterase (AChE) activity. Results of the present study demonstrate that ciproxifan and clobenpropitwere able to control AMPH and MK-801-induced hyperlocomotor activities demonstrated as reduced horizontal activity and reduced number of movements made by rats. Further, there was overall reduction in APO-induced climbing behavior. Learning and memory deficits, as evaluated on elevated plus maze, followed by estimation of brain AChE activity demonstrated positive results with these protypical imidazole H(3)R-antagonists/inverse agonists.

Topics: Acetylcholinesterase; Animals; Behavior, Animal; Brain; Catalepsy; Female; Histamine Antagonists; Imidazoles; Learning Disabilities; Ligands; Male; Memory Disorders; Mice; Motor Activity; Rats; Rats, Wistar; Receptors, Histamine H3; Schizophrenia; Thiourea