Intake of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) leads to symptoms of Parkinson's disease and produces degeneration of nigrostriatal dopaminergic neurons in humans, giving rise to the hypothesis that this disorder may be caused by endogenous or environmental toxins. Excitation mediated by dicarboxylic amino acids such as L-glutamate or L-aspartate, has been claimed to be involved in pathogenesis of neurodegenerative disorders. We therefore sought to determine whether antagonists active at the NMDA or quisqualate subtypes of L-glutamate receptors prevent toxicity of either MPP+ (1-methyl-4-phenyl-pyridinium ion, the active metabolite of MPTP) or the selective dopaminergic neurotoxin 6-OHDA in the rat substantia nigra pars compacta. We report here that certain selective NMDA antagonists (AP7, CPP, MK-801), but not the preferential quisqualate antagonists CNQX and NBQX, provided short-term (up to 24 h) protection against MPP+ toxicity when coadministered into the substantia nigra. Systemic administration of CPP or MK-801 also offered temporary protection for up to 4 h against MPP+ toxicity. Repeated systemic administration of either compound prolonged protection against MPP+ challenge. Repeated administration for at least 24 h also led to permanent protection, still evident 7 days after intranigral administration of MPP+.
In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) the cytokines tumour necrosis factor-alpha (TNF), lymphotoxin-alpha (LT), and interferon-gamma (IFN-gamma) are of central pathogenetic importance. A therapy capable of stopping neurological deterioration in MS patients is not yet available. Here, we report that rolipram, a selective type IV phosphodiesterase inhibitor, stereospecifically suppresses the production of TNF/LT and less strongly also IFN-gamma in human and rat auto-reactive T cells. Moreover, we show that rolipram is an effective treatment for EAE. Rolipram has extensively been studied in humans for the treatment of depression, but has not yet been marketed. The data presented here identify rolipram as potential therapy for multiple sclerosis and provoke the immediate initiation of clinical trials.
Over the past few decades, research on Alzheimer’s disease (AD) has focused on pathomechanisms linked to two of the major pathological hallmarks of extracellular deposition of beta-amyloid peptides and intra-neuronal formation of neurofibrils. Recently, a third disease component, the neuroinflammatory reaction mediated by cerebral innate immune cells, has entered the spotlight, prompted by findings from genetic, pre-clinical, and clinical studies. Various proteins that arise during neurodegeneration, including beta-amyloid, tau, heat shock proteins, and chromogranin, among others, act as danger-associated molecular patterns, that—upon engagement of pattern recognition receptors—induce inflammatory signaling pathways and ultimately lead to the production and release of immune mediators. These may have beneficial effects but ultimately compromise neuronal function and cause cell death. The current review, assembled by participants of the Chiclana Summer School on Neuroinflammation 2016, provides an overview of our current understanding of AD-related immune processes. We describe the principal cellular and molecular players in inflammation as they pertain to AD, examine modifying factors, and discuss potential future therapeutic targets.
Summary. Degeneration of dopaminergic nigrostriatal neurons in Parkinson's disease results in an overactivity of excitatory glutamatergic projections from the subthalamic nucleus to the output nuclei of the basal ganglia resulting in rigidity and akinesia. In theory pharmacological blockade of these overactive systems should improve parkinsonian symptomatology. The selective AMPAantagonist NBQX and the competitive NMDA-antagonist CPP are not effective in animal models of Parkinson's disease when given alone but ameliorate parkinsonian symptomatology and stimulate locomotor activity when co-administered with a threshold dose of L-Dopa. These synergistic effects are seen in the MPTP-treated (1-methyl-4-phenyl-l,2,3,6-tetrahydropyridine) common marmoset and the rat with unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra. Therefore competitive NMDA and non-NMDA antagonists may offer a new therapeutic strategy for the treatment of Parkinson's disease.
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