The etiology of idiopathic Parkinson's disease remains as an enigma. N-Methyl(R)salsolinol [NM(R)Sal] is a candidate of dopaminergic neurotoxins, and is synthesized from dopamine by 2 enzymes: (R)Salsolinol synthase and a neutral (R) Salsolinol N-methyltransferase (nNMT). NM (R) Sal injection in the rat striatum caused selective depletion of dopamine neurons in the substantia nigra without tissue reaction, suggesting NM(R)Sal induced apoptosis in dopamine neurons. NM(R)Sal level was found to increase significantly in the cerebrospinal fluid of parkinsonian patients, and NM(R)Sal accumulated in the nigrostriatum. By the analysis of the human brain, it was suggested nNMT is the rate-limiting step to synthesize dopamine-derived neurotoxins. The activity of nNMT was found to increase in the lymphocytes from parkinsonian patients. The mechanism of toxicity by NM(R)Sal was studied in vitro using human dopaminergic neuroblastoma SH-SY5Y cells. NM(R)Sal induced apoptosis stereo-specifically, suggesting that a molecule in mitochondria can distinguish the stereo-chemical structure of NM(R)Sal and activate intracellular signal of apoptosis. Recently, we found that propargylamines, inhibitors of type B monoamine oxidase, can prevent the apoptosis induced by NM(R)Sal. Further study on the mechanism underlying increase in nNMT activity in parkinsonian patients will clarify the involvement of genetic and environmental factors in the pathogenesis of Parkinson's disease.

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Extracellular ATP has been known to activate sensory neurons via the ATP-gated ion channels P2X receptors, leading to the proposal that the P2X receptors may play a role in signal transduction of pain from the peripheral site to the spinal cord in vivo. P2X₃ receptors are expressed in capsaicin-sensitive small-sized dorsal root ganglion (DRG) neurons, and they are involved in the generation of rapidly desensitizing inward current and evoking nocifensive behavior and thermal hyperalgesia. Heteromeric P2X_2/3 (P2X₂ and P2X₃) receptor is expressed in capsaicin-insensitive primary afferent fibers, and its activation leads to the generation of slow desensitizing currents and induction of mechanical allodynia. In addition, accumulating information suggests the involvement of G protein-coupled ATP receptors in the modulation of the generation and transmission of pain.

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Mechanical stress to cells induces various physiological cellular responses and pathophysiological changes in many cell types. However, the molecular mechanisms remain unclear. Clarification of the mechanosensor mechanisms on the molecular level may provide an alternative approach for the development of new drugs. In the 73rd Annual Meeting of The Japanese Pharmacological Society, the latest studies performed by the following five departments were reported and discussed: 1) Expression of putative stretch sensitive nonselective cation channels of mammal, by M. Suzuki et al. (Department of Pharmacology, Jichi Medical School) ; 2) Mechanosensitive ATP release in aortic endothelial cells, by M. Oike et al. (Department of Pharmacology, Graduate School of Medical Science, Kyushu University) ; 3) Lysophosphatidic acid acts as an endogenous modulator on mechanotransduction, by H. Ohata et al. (Department of Pharmacology, School of Pharmaceutical Sciences, Showa University) ; 4) Stretch-induced myosin light chain phosphorylation without force development in canine basilar artery, by K. Obara et al. (Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka) ; and 5) Transcriptional regulation of smooth muscle phenotypic modulation, by R. Nagai (Department of Cardiovascular Medicine, University of Tokyo). This article reviews these reports.

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Recombinant adenoviruses are attracting a great deal of attention as a highly efficient gene delivery technology and used for in vitro and in vivo gene expression in science. However, among traditional methods, there have been many difficulties and no simple procedure to generate recombinant adenoviruses. Since almost of all these methods involve the process of homologous recombination in a mammalian packaging cell line, the problems are low efficiency of homologous recombination, the need for complicated techniques and the demand for a long time to generate recombinant viruses. These problems have prevented widespread use of adenovirus technology as effective gene transfer tools. In the last few years, there have been several significant and innovative advances in adenoviral technologies, which include a new generation of vectors, the ease of vector manipulation and improvement of the viral production system with homologous recombination in E. coli. Here, we describe the easier and more efficient viral production systems and provide a practical manual for generating recombinant adenoviruses based on one of such systems.

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We examined the effects of fudosteine [(-)-(R)-2-amino-3-(3-hydroxypropylthio) propionic acid], a new cysteine derivative, on aiway secretion in rabbits and rats. Indirect measurement of airway secretion in rabbits, which was expressed by the amount of dye excreted into the respiratory tract, was carried out according to the Sakuno's method, with some modifications. Fudosteine (500 mg/kg, p.o.) significantly increased the amount of dye excreted into the respiratory tract. As a direct method of measurement of airway secretion, the modified Perry and Boyd's method was used to collect respiratory tract fluid (RTF) in rabbits. Fudosteine (500 mg/kg, p.o.) significantly augmented the output volume of RTF, but there was no difference from the control in protein and phosphatidylcholine (PC) contents into RTF. On the other hand, fudosteine increased chloride ion concentration in broncho-alveolar lavage of rats. Fudosteine did not stimulate PC secretion in a primary culture of rat type II pneumocytes, and it did not have a mucolytic effect against gastric mucin in vitro. From the results described above, it was concluded that fudosteine may be a new cysteine derivative which offers a serous secretion.

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Stroke represents the third common cause of death and hospitalization. However, there are yet no drugs that have reliable effects on acute stroke in Japan. Therefore, the development of new drugs that can support patients is required. There are various candidate drugs for acute stroke such as antithrombotic agents, anticoagulants, thrombolytic agents, neuroprotectants, and so on. Recently clinical trials suggest that aspirin may improve outcome, although these studies demonstrated a modest benefit of aspirin. Abciximab (ReoPro) is a human/mouse monoclonal antibody directed against the platelet receptor glycoprotein IIb/ IIIa. It appears to be safe and might improve functional outcome. The large randomized trails were started to test the hypothesis that thrombolysis by an intravenous administration of a recombinant tissue type plasminogen activator (rtPA) could restore cerebral blood flow and improve patient outcome in acute ischemic stroke. These results can support the use of intravenous rtPA for stroke treatment within 3 h after onset, but not beyond 3 h. Development of an effective neuroprotective agent for the treatment of acute stroke remains problematic. Antioxidants, MCI-186 and ebselen, have finished phase III of clinical trials in Japan and were effective. We hope that efficacious drugs for acute stroke can be used for patients.

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According to the “Guideline for Diagnosis and Treatment of Asthma” established by the Japanese Society of Allergy in 1998, inhaled adrenergic β₂ agonists and inhaled corticosteroids are recommended for treatment of asthma. Thereafter, the development of new drugs for the treatment of asthma has begun changing. The concepts upon which the development of investigational drugs for asthma are based include improvements of drug delivery systems (ease of use, long-acting preparations, fewer side-effects), device design and appropriate auxiliary instrumentation. Moreover, chronic asthma has come to be recognized as an inflammatory disease of airway mucosa. At present, various antiallergic compounds such as tachykinin, leucotrien, PAF antagonists and others are under investigation thanks to the identification of new chemical mediators of airway inflammation and studies have progressed to the synthesis and manufacturing of new pharmaceuticals with antagonistic action. Thus, this review classified and introduced various new investigational anti-asthma and further describes the structure-activity relationships of β₂ agonists and inhaled corticosteroids.

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