Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fourteen di- and tripeptide analogues of MIF, Pro-Leu-Gly-NH2, have been synthesized and assayed for inhibition of oxotremorine-induced tremor. Replacement of Pro by HCO-Pro or cyclopentanecarboxylic acid gave inactive analogues, while some peptides of the general structure less than Glu-Leu-Gly-NR1R2 were highly active. Thus, R1 = C3H8 and R2 = H gave 4 times the activity of MIF, R1 = I-C3H8 and R2 = H gave 13 times the activity of MIF, and R1 = R2 = CH3 gave 29 times the activity of MIF. cyclo(-Pro-Leu-), Pro-Lys-Gly-NH2, and Pro-Arg-Gly-NH2 had no activity. Apparently, small modifications in the structure of MIF can yield highly active analogues with potential clinical value, e.g., in the treatment of Parkinson's disease or mental depression.
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PMID:Tripeptide analogues of melanocyte-stimulating hormone release-inhibiting hormone (Pro-Leu-Gly-NH2) as inhibitors of oxotremorine-induced tremor. 4 28

A number of questions remain unsettled about the release of melanocyte-stimulating hormone (MSH) and about its function. Even though relatively few investigators are studying this area, some generalities have emerged during the last 10 years. It now seems that release of MSH from the pituitary is inhibited by a substance present in the hypothalamus. The structure of this physiologic inhibitor of MSH release may still not be considered an established entity but there is evidence for additional mechanisms capable of exerting a fine control on the release of MSH. Contrary to some opinions, the release of MSH does not always occur together with the release of ACTH, and the release of the two hormones can be dissociated in several laboratory and clinical situations. In addition, many studies have shown that the pituitary peptide, MSH, exerts behavioral and electroencephalographic effects in both the rat and man. The hypothalamic peptide Pro-Leu-Gly-NH2 (MIF-I) also has direct effects on the central nervous system that may include alleviation of the symptoms of Parkinson's disease.
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PMID:Some questions related to melanocyte-stimulating hormone. 96 14

Amine accumulation is observed in the lateral hypothalamus (LH) after nigrostriatal neurons degenerate. It has been proposed that this accumulation is a source of amines which are released into the hypothalamus thereby affecting the function of adjacent aminergic receptors. To approximate this condition of continuous exposure of LH receptors to endogenous amines, dopamine (DA) was injected into the LH of rats once daily for 5 consecutive days. A control group received 4 daily injections of tartaric acid vehicle and then DA on day 5. Rats pretreated with DA showed severe impairment of open field performance and motor reflex control on day 5 when they were compared to control animals which received vehicle pretreatment. In a second study, the DA receptor antagonist haloperidol was injected into the area of amine accumulation in the LH to determine whether this might block amine release from areas of accumulation thereby to attenuate lesion-induced rotation. Haloperidol administered once daily for 4 out of 7 days, once daily for 7 days or via a continuous infusion for 7 days, all reduced d,l-amphetamine-induced turning to control levels. These results suggest that prolonged exposure of hypothalamic DA receptors alters their sensitivity to subsequent doses of DA and that amine released from areas of accumulation may be blocked by haloperidol to enhance behavioral recovery from DA depleting lesions. Moreover, these findings indicate that the hypothalamus participates in the behavioral effects induced by DA depleting lesions and highlight the importance of hypothalamic pathology in Parkinson's disease.
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PMID:Sensitivity of dopamine receptors in the lateral hypothalamus is altered in 6-hydroxydopamine treated rats. 134 83

We are currently developing amino-substituted MPTP analogues as useful probes for understanding the mechanism of MPTP toxicity and Parkinson's disease. One analogue, 4'-amino MPTP, induces a loss of striatal dopamine and is thus a suitable substitute for MPTP. This probe will be used as a histologically fixable MPTP which can be used to answer detailed anatomical questions concerning the sites of MPTP, MPP+ uptake and storage. In addition, antibodies have been raised against MPTP and MPP+ in rabbits using diazo-linked bovine serum albumin conjugates. The antibodies have been characterized with regard to their recognition of relevant structural analogues using an enzymelinked immunoassay (ELISA) procedure. Antibodies to MPTP detected MPTP in mouse brain extracts derived from as little as 5 micrograms of tissue. The antibodies will be used for immunohistochemical localization of 4'-NH2-MPTP and 4'-NH2-MPP+ in brain, as well as probes for the screening of parkinsonian brain tissue for any MPTP- or MPP+-like materials which might exist.
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PMID:The development of amine substituted analogues of MPTP as unique tools for the study of MPTP toxicity and Parkinson's disease. 243 63

Primary care physicians have a vital role to play in identifying depression in their elderly patients. Diagnosis may be difficult, because symptoms are atypical and frequently include psychomotor agitation, somatic symptoms, and complaints of memory loss. Patients with medical illnesses, such as cancer, postmyocardial infarction, stroke, Parkinson's disease, and early Alzheimer's disease are particularly vulnerable to depression. Drugs that may cause depressive symptoms are digitalis at toxic levels, beta-blockers, centrally acting antihypertensives, immunosuppressants, and nonsteroidal anti-inflammatory agents. Cyclic antidepressants are the drugs of first choice. Selection depends on the patient's physical health and current medications and the side effect profile of the drug. Side effects are more pronounced in old age because of drug accumulation owing to slowed clearance. Troublesome side effects are anticholinergic effects, orthostatic hypotension, sedation, cardiotoxicity, and weight gain. The most useful antidepressants for geriatric patients are the secondary amines, desipramine and nortriptyline. The second-generation drug trazodone has the advantage of causing the least anticholinergic effects, but it is very sedating. Before treatment, the patient should have an electrocardiogram, liver function tests, tonometry, sitting and standing blood pressures, evaluation of urinary symptoms for outflow obstruction, review of current medications, and estimation of suicide risk. Cyclic antidepressants are contraindicated during recovery from myocardial infarction, in heart disease when there is severe impairment of myocardial performance, in seizure disorders, and in the presence of glaucoma or a large prostate. Drug interactions that may cause trouble can occur with epinephrine, MAO inhibitors, thyroid hormone, cimetidine, and centrally acting antihypertensives. Dosage should start low, increasing usually by 25 mg every 4 to 5 days until a therapeutic level is reached. Failure of a noradrenergic antidepressant after 4 to 5 weeks can be followed by a trial of a serotonergic drug. Drug serum level monitoring is useful for imipramine, desipramine, and nortriptyline. Monoamine oxidase inhibitors are effective in many elderly patients who are resistant to TCAs. Sympathomimetic drugs must be avoided with MAOIs. Elderly patients are at high risk of toxicity and drug interactions with lithium. Electroconvulsive therapy is useful for patients who do not respond to drug treatment, but medical complications, particularly cardiovascular, often occur in patients 75 or older. Many patients relapse after ECT. Psychotherapy together with pharmacotherapy may be the optimal treatment for elderly depressives. Older patients are more likely to become chronically depressed than younger patients. The risk of suicide in depressed elderly males is high, particularly in those with psychosocial problems, and depression rises with age.
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PMID:Management of depression in the elderly. 266 41

Amine accumulation in the axons of degenerating, amine-containing neurones is a natural component of neurone death in many species, including man. While it is becoming increasingly clear that this phenomenon may have functional significance in animal models of Parkinson's Disease, its potential importance in the clinical syndrome has been pretermitted. There are several reasons for this. Failure to sample tissue which contains accumulated amines, the masking of accumulation by adjacent depleted tissues and the degradation of accumulated amines in post-mortem tissues from Parkinsonian brains could account for the low incidence of detection of accumulation in this disorder. Increased levels of amines have been detected in the brains of patients with other conditions including cerebral infarction, Alzheimer's Disease and Huntington's Chorea. These increases have been attributed previously to enhanced aminergic activity, rather than a stage in the degenerative process, as our hypothesis suggests. In addition to the potential importance of amine accumulation in the pathophysiology of various clinical syndromes, a more thorough investigation of this phenomenon in animal models would seem essential since they are used routinely to both describe the basic principles of dopamine function and to evaluate therapeutic possibilities in Parkinson's Disease.
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PMID:Amine accumulation in Parkinson's disease and other disorders. 295 7

For several years there is controversy concerning the toxic potency of reaction products catalyzed by monoamine oxidase in neurodegenerative processes. There is uncertainty whether products of catecholamine oxidation are pathogenetically relevant factors for neuronal cell death in Parkinson's disease. To date products responsible for impairment of biochemical functions essential for cell viability are not yet identified, and the primary site of damage within the cell is unknown. Ammonia, aldehydes and hydrogen peroxide are formed via monoamine oxidase catalyzed oxidations of primary amines. But which of them, if any, is damaging to the cell? We discuss some aspects of the oxidative stress theory of cell degeneration in relation to toxicity of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and to monoamine oxidation. Furthermore, we consider possible functional relationships of mitochondrial electron transfer reactions, toxicity of MPTP and MAO activity.
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PMID:Influence of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, lipoic acid and L-deprenyl on the interplay between cellular redox systems. 788 97

In the present study, L-prolyl-L-leucyl-glycinamide (1) peptidomimetics 3a-3d and 4a-4d were synthesized utilizing alpha, alpha-disubstituted amino acids. These analogues were designed to explore the conformational effects of constraints at the phi3 and psi3 torsion angles. Constrained conformations were verified by the use of X-ray crystallography and circular dichroism. The effects of Pro-Leu-Gly-NH2 analogues 3a-3d and 4a-4d on enhancing rotational behavior induced by apomorphine in the 6-hydroxydopamine-lesioned animal models of Parkinson's disease were studied. The ability of these peptidomimetics to increase the binding of agonist N-propylnorapomorphine (NPA) to the dopamine D2 receptor was also examined. Extended analogue Pro-Leu-Deg-NH2 was the most active compound of this series. It was 10 times more potent and almost 2 times more effective than 1 in increasing apomorphine-induced rotations (56 +/- 15% at 1.0 mg/kg ip) and in enhancing [3H]NPA specific binding (40%).
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PMID:Synthesis and dopamine receptor modulating activity of novel peptidomimetics of L-prolyl-L-leucyl-glycinamide featuring alpha,alpha-disubstituted amino acids. 1021 30

Nicotinic acetylcholine receptors (nAChRs) are membrane-bound, pentameric ligand-gated ion channels associated with a variety of human disorders such as Alzheimer's disease, Parkinson's disease, schizophrenia, and pain. Most known nAChRs contain an unusual eight-membered disulfide-containing cysteinyl-cysteine ring, ox-[Cys-Cys], as does the soluble acetylcholine binding protein (AChBP) found in the snail Lymnaea stagnalis. The cysteinyl-cysteine ring is located in a region implicated in ligand binding, and conformational changes involving this ring may be important for modulation of nAChR function. We have studied the preferred conformations of Ac-ox-[Cys-Cys]-NH2 by NMR in water and computationally by Monte Carlo simulations using the OPLS-AA force field and GB/SA water model. ox-[Cys-Cys] adopts four distinct low-energy conformers at slightly above 0 degrees C in water. Two populations are dependent on the peptide omega2 dihedral angle, with the trans amide favored over the cis amide by a ratio of ca. 60:40. Two ox-[Cys-Cys] conformers with a cis amide bond (C+ and C-) differ from each other primarily by variation of the chi3 dihedral angle, which defines the orientation of the helicity about the S-S bond (+/- 90 degrees ). Two trans amide conformers have the same S-S helicity (chi3 approximately -90 degrees ), but are distinguished by a backbone rotation about phi2 and psi1 (T- and T'-). The ratio of T-/T'-/C+/C- is 47:15:29:9. The orientation of the pendant moieties from the eight-membered ring is more compact for the major trans conformer (T-) than for the extended conformations adopted by T'-, C+, and C-. These conformational preferences are also observed in tetrapeptide and undecapeptide fragments of the human alpha7 subtype of the nAChR that contains the ox-[Cys-Cys] unit. Conformer T- is nearly identical to the conformation seen in the X-ray structure of ox-[Cys(187)-Cys(188)] found in the unliganded AChBP, and is a Type VIII beta-turn.
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PMID:Conformational analysis of the eight-membered ring of the oxidized cysteinyl-cysteine unit implicated in nicotinic acetylcholine receptor ligand recognition. 1174 32

The c-Jun NH2-terminal Kinase (JNK) signaling pathway is frequently induced by cellular stress and correlated with neuronal death. This unique property makes JNK signaling a promising target for developing pharmacological intervention. Among several neurological disorders, JNK signaling is particularly implicated in ischemic stroke and Parkinson's disease. The inhibitors of the JNK signaling pathway include upstream kinase inhibitors (for example, CEP-1347), small chemical inhibitors of JNK (SP600125 and AS601245), and peptide inhibitors of the interaction between JNK and its substrates (D-JNKI and I-JIP). The mechanisms by which JNK signaling induces apoptosis and evidence of cytoprotective effects of these JNK inhibitors are summarized in the present review.
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PMID:Targeting the JNK signaling pathway for stroke and Parkinson's diseases therapy. 1572 14


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