The significance of selegiline/(−)-deprenyl after 50 years in research and therapy (1965–2015)

Deprenyl/Selegiline (DEP), created by Joseph Knoll in the 1960s, registered in more than 60 countries to treat Parkinson’s disease, Alzheimer’s disease, major depressive disorder; and used as an anti-aging drug, achieved its place in research and therapy as the first selective inhibitor of B-type monoamine oxidase (MAO-B). The demonstration that the DEP analog (−)-1-phenyl-2-propylaminopentane devoid of MAO inhibitory property, enhanced like DEP the activity of the catecholaminergic brain engine revealed that this effect is unrelated to the selective inhibition of MAO-B. β-Phenylethylamine (PEA), the important trace-amine in the mammalian brain, is known to be a releaser of catecholamines. Amphetamine and methamphetamine, the best known synthetic PEA derivatives are also releasers of catecholamines like their parent compound. DEP is a unique synthetic PEA derivative devoid of the catecholamine releasing property. As the releasing effect conceals the catecholaminergic activity enhancer (CAE) effect, it remained undiscovered until DEP uncovered that PEA is a natural CAE substance; and only releases catecholamines in high concentration. Discovering that tryptamine is a natural enhancer of catecholaminergic and serotonergic neurons catalyzed the development of R-(−)-1-(benzofuran-2-yl)-2-propylaminopentane (BPAP); the most potent and selective enhancer substance, and it exerts its enhancer effect in 0.0001 mg kg-1. DEP and BPAP initiated an analysis of the enhancer regulation in the mammalian brain. Studies regarding the nature of the enhancer regulation revealed that this regulation is enhanced after weaning and sex hormones return it to the pre-weaning level. Thus, sex hormones elicit the transition of the developmental phase of life into the post-developmental, downhill (aging) period. The aging-related, slow decline in the enhancer regulation of the catecholaminergic brain engine, the main activator of the cortex, is the prime factor of brain aging. The enhancer regulation’s decay in the most rapidly aging dopaminergic system is, for example, mainly responsible for the decline in learning ability and sexual activity over time. According to the Knoll concept, based on two longevity studies performed on male rats, to keep the catecholaminergic brain engine, from the beginning of the downhill period of life, via the administration of a small daily dose of a CAE substance (presently DEP is the only available drug) on a higher activity level, thus to fight against the physiological aging-related slow decay of the catecholaminergic system, is a suitable anti-aging therapy. As our present knowledge regarding the enhancer regulation in the mammalian brain is like seeing a peak of an iceberg, the future of this new line of brain research looks promising from both theoretical and practical aspects.Molecular Psychiatry advance online publication, 2 August 2016; doi:10.1038/mp.2016.127. © 2016 Macmillan Publishers Limited, part of Springer Nature

A parkin szerepe a Parkinson-kórban

Parkin (Parkinson juvenile disease protein 2) is a ~52 kDa (426 amino acid) enzyme protein, encoded by PARK2 gene and located on the 6q chromosome. It plays an important role in the ubiquitin-proteasome system and acts as a regulator of protein breakdown. Parkin is located in the cytoplasma until a sustained depolarization occurs as a result of which it is translocated to the mitochondrial surface and induces the degradation of various membrane proteins which are candidates for mitophagia. Parkin is essential for cellular mitochondrial integrity. Parkin mutation leads to the accumulation of missfolded, aggregated proteins and degenerated mitochondria. The role of these changes in the pathomechanism of neurodegenerative diseases is well-known. It was a general belief for a long time that Parkinson's disease is without genetic component a sporadic disease. In 1997 a point mutation was, however, discovered in the alpha-synuclein gene, which caused dominantly inherited parkinsonism. At least 10 other genes were thereafter detected the mutation or deletion of which cause monogenic parkinsonism. Parkin mutation is responsible for about 50% of familial cases and for 10 to 20% of youth cases. According to the present views the improper regulation of protein aggregation and a dysfunction of the ubiquitin-proteasome system may be the common pathway of sporadic and hereditary Parkinson's disease. In the future it might have therapeutic value that parkin has versatile neuroprotective activity (against alpha-synuclein toxicity, proteasomal dysfunction, oxidative stress, kainite-induced and dopamine-mediated toxicity) as a result of which any reduction of parkin level or activity may cause damage in neuronal integrity

Geroprotection in the future. In memoriam of Joseph Knoll

In memoriam of Joseph Knoll: the selegiline story continues

Essential difference between the pharmacological spectrum of (À)-deprenyl and rasagiline

Introduction Knoll developed E-250, later named deprenyl, an MAO inhibitor with a peculiar pharmacological spectrum in the late 1960s Later on, the DATATOP Multicenter Clinical Study revealed that the administration of (À)-deprenyl to untreated patients with PD significantly delays the need for levodopa therapy Knoll's further studies into the mechanism of action of (À)-deprenyl revealed that: (i) a peculiar catecholaminergic activity enhancer (CAE) regulation is operating in the brain stem's catecholaminergic neuron

Longevity study with low doses of selegiline/(-)-deprenyl and (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine (BPAP)

AIMS: The first longevity study demonstrating that rats treated with the MAO-B inhibitory dose of (-)-deprenyl (0.25mg/kg) lived significantly longer than their saline-treated peers was published in 1988, and corroborated in many papers. The recent findings that (-)-deprenyl is primarily a PEA-derived synthetic catecholaminergic activity enhancersubstance; (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine (BPAP) is a tryptamine-derived synthetic enhancer substance, initiated our first longevity study on rats with low enhancer doses of (-)-deprenyl and BPAP to test the enhancer effect's role inlife extension. MAIN METHODS: We used the shuttle box technique for selecting the optimum doses of (-)-deprenyl and BPAP. (-)-Deprenyl exerts in rats in 0.001mg/kg its 'specific' enhancer effect and in 0.1mg/kg its 'non-specific' enhancer effect. BPAP exerts its 'specific' enhancer effect in 0.0001mg/kg and its 'non-specific' enhancer effect in 0.05mg/kg. Groups of male Wistar rats (N=40) were treated subcutaneously from their 10th week until death, three times weekly, with saline (0.5ml/kg), and the selected doses of (-)-deprenyl or BPAP, respectively. As an indicator of aging we tested the age-related changes in their learning ability. KEY FINDINGS: Rats treated with 0.0001 or 0.05mg/kg BPAP lived significantly longer than their saline treated peers (P<0.02) and BPAP was more potent in extending rats' lifespan than (-)-deprenyl. 18-month-old rats treated with 0.0001mg/kg BPAP were as good learners as 3-month-old saline treated rats. SIGNIFICANCE: The study revealed that the enhancer effect is responsible for life extension

Az alpha-szinuklein szerepe Parkinson-kórban

alpha-synuclein, a small protein (140 amino acids) encoded by the SNCA gene is the best known isoform of the synuclein protein family. Though its physiological role is still not fully clarified, there is growing experimental evidence for a causal role of alpha-synuclein in the so-called conformational-neurodegenerative diseases. Conformational changes in the structure of the native soluble protein form insoluble neurotoxic aggregates and finally contribute to the formation of inclusion Lewy-bodies and Lewy-neurites. Neurodegeneration first hits the olfactory system, the peripheral autonomic nervous system, the enteric nervous system and the dorsal vagal motoneurons. The middle stage of the disease hits the dopaminergic neurons of the substantia nigra; and the neocortex is affected only in the late stage of the disease. This precise order of neurodegeneration is not always valid, but increases the likelihood that Lewy-bodies and neurodegenaration spread to intact areas in a prion-like way. Prions are infectious proteins which do not contain nucleic acids and cause diseases because they form toxic aggregates and filaments by misfolding in a beta-sheet-rich conformation. The misfolded protein behaves like a template inducing conformational change in the wild type proteins causing cross-reaction and leading to neurodegeneration. Later, the defective proteins may infect healthy nerve cells, thus neurodegeneration is extended. Growing experimental evidence shows that monomers and aggregates of alpha-synuclein are secreted via exocytosis from damaged nerve cells and taken up via endocytosis by healthy nerve cells furnishing evidence for the prion-like role of alpha-synuclein