Journal of Pharmacological Sciences
Online ISSN : 1347-8648
Print ISSN : 1347-8613
ISSN-L : 1347-8613
Volume 120 , Issue 3
Showing 1-13 articles out of 13 articles from the selected issue
Current Perspective
  • Zhi-Li Ren, Ping-Ping Zuo
    2012 Volume 120 Issue 3 Pages 139-145
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 26, 2012
    JOURNALS FREE ACCESS
    The effects of a single compound and a mixture of traditional Chinese medicine (TCM) on promoting proliferation, differentiation, and migration of neural stem cells and regulating their microenvironment have been observed by Chinese scholars in recent years. These results showed good prospects in improving neural regeneration and repair of neurological disorders such as ischemic brain injury, Alzheimer’s disease, Parkinson’s disease, and depression. According to the TCM theory, the relationship between life of an individual and the disease was regarded as an entirety, and the theory emphasized the treatment based on syndrome differentiation since ancient times. In this paper, we attempted to introduce these medicines, which belong to natural products and have already been proved to possess clear therapeutic action on human bodies in the clinical setting. We summarized their effects promoting brain neurogenesis and repairing brain injuries in animal models and some mechanisms at the cellular and molecular levels.
    Download PDF (165K)
  • Kazuo Takahama
    2012 Volume 120 Issue 3 Pages 146-151
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 10, 2012
    JOURNALS FREE ACCESS
    Antitussive drugs have been used for decades and their modes of action are well elucidated. However, recent studies on the mechanism of their antitussive action seem to be opening a new way for discovery or development of novel drugs for intractable brain diseases including psychiatric disorders. Antitussives inhibit the currents caused by activation of G protein-coupled inwardly rectifying K+ (GIRK) channels in neurons. In our own studies carried out so far, we found that antitussives possessing an inhibitory action on GIRK channels, similar to the effects of an enriched environment, ameliorate symptoms of intractable brain diseases in various animal models. In this review, the multiple pharmacological actions of the antitussives are described, and their mechanisms are discussed addressing GIRK channels as a possible molecular target.
    Download PDF (255K)
Critical Review
  • Hiroko Ikeda, Junzo Kamei, Noriaki Koshikawa, Alexander R. Cools
    2012 Volume 120 Issue 3 Pages 152-164
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 10, 2012
    JOURNALS FREE ACCESS
    Accumbal dopamine plays an important role in physiological responses and diseases such as schizophrenia, Parkinson’s disease, and depression. Since the nucleus accumbens contains different neurotransmitters, it is important to know how they interact with dopaminergic function: this is because modifying accumbal dopamine has far-reaching consequences for the treatment of diseases in which accumbal dopamine is involved. This review provides a summary of these interactions, and our current knowledge about them are as follows: A) AMPA receptors are required for dopamine-dependent behavior and vice versa; NMDA receptors modulate the activity at the level of AMPA and/or dopamine D1 receptors. B) GABAA, but not GABAB, receptors inhibit dopamine-dependent behavior. C) Nicotinic receptors are required for dopamine-dependent behavior, whereas muscarinic receptors inhibit dopamine-dependent behavior. D) α-Adrenoceptors inhibit dopamine-dependent behavior in contrast to β-adrenoceptors, which potentiate this behavior. E) μ- and δ2-opioid receptors elicit behavior that requires an intact dopaminergic function and δ2-opioid receptors modulate dopamine-dependent behavior. F) Orexin 2 receptors play an important, modifying role in dopamine-dependent behavior. G) Somatostatin receptors potentiate dopamine-dependent behavior. It is suggested that modulation of the above-mentioned non-dopaminergic receptors provide new tools to control physiological functions as well as diseases mediated by accumbal dopamine.
    Download PDF (233K)
Full Paper
  • Akira Takahara, Kaori Fujiwara, Atsushi Ohtsuki, Takayuki Oka, Iyuki N ...
    2012 Volume 120 Issue 3 Pages 165-175
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 06, 2012
    JOURNALS FREE ACCESS
    Cloperastine is an antitussive drug, which can be received as an over-the-counter cold medicine. The chemical structure of cloperastine is quite similar to that of the antihistamine drug diphenhydramine, which is reported to inhibit hERG K+ channels and clinically induce long QT syndrome after overdose. To analyze its proarrhythmic potential, we compared effects of cloperastine and diphenhydramine on the hERG K+ channels expressed in HEK293 cells. We further assessed their effects on the halothane-anesthetized guinea-pig heart under the monitoring of monophasic action potential (MAP) of the ventricle. Cloperastine inhibited the hERG K+ currents in a concentration-dependent manner with an IC50 value of 0.027 μM, whose potency was 100 times greater than that of diphenhydramine (IC50; 2.7 μM). In the anesthetized guinea pigs, cloperastine at a therapeutic dose of 1 mg/kg prolonged the QT interval and MAP duration without affecting PR interval or QRS width. Diphenhydramine at a therapeutic dose of 10 mg/kg prolonged the QT interval and MAP duration together with increase in PR interval and QRS width. The present results suggest that cloperastine may be categorized as a QT-prolonging drug that possibly induces arrhythmia at overdoses like diphenhydramine does.
    Download PDF (545K)
  • Katsura Takano, Hiroshi Yamasaki, Kenji Kawabe, Mitsuaki Moriyama, Yoi ...
    2012 Volume 120 Issue 3 Pages 176-186
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 16, 2012
    JOURNALS FREE ACCESS
    Depression is one of the most prevalent and livelihood-threatening forms of mental illnesses and the neural circuitry underlying depression remains incompletely understood. Recent studies suggest that the neuronal plasticity involved with brain-derived neurotrophic factor (BDNF) plays an important role in the recovery from depression. Some antidepressants are reported to induce BDNF expression in vivo; however, the mechanisms have been considered solely in neurons and not fully elucidated. In the present study, we evaluated the effects of imipramine, a classic tricyclic antidepressant drug, on BDNF expression in cultured rat brain astrocytes. Imipramine dose-dependently increased BDNF mRNA expression in astrocytes. The imipramine-induced BDNF increase was suppressed with inhibitors for protein kinase A (PKA) or MEK/ERK. Moreover, imipramine exposure activated transcription factor cAMP response element binding protein (CREB) in a dose-dependent manner. These results suggested that imipramine induced BDNF expression through CREB activation via PKA and/or ERK pathways. Imipramine treatment in depression might exert antidepressant action through BDNF production from astrocytes, and glial BDNF expression might be a target of developing novel antidepressants.
    Download PDF (272K)
  • Kazuyoshi Kawakami, Terumasa Chiba, Nobuyuki Katagiri, Maya Saduka, Ke ...
    2012 Volume 120 Issue 3 Pages 187-195
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 20, 2012
    JOURNALS FREE ACCESS
    Peripheral neuropathic pain is a serious side effect of paclitaxel treatment. However, the mechanism of this paclitaxel-induced neuropathic pain is unknown. In this study, we investigated the effects of paclitaxel on the voltage-dependent calcium channel (VDCC) current in rat dorsal root ganglion (DRG) neurons using the whole-cell patch clamp technique. Behavioral assessment using von Frey filament stimuli showed that 2 and 4 mg/kg paclitaxel treatment induced mechanical allodynia/hyperalgesia. Paclitaxel-induced mechanical hyperalgesia was significantly inhibited by gabapentin (100 mg/kg). Using the patch clamp method, we observed that paclitaxel (4 mg/kg) treatment significantly increased the VDCC current in small- and medium-diameter DRG neurons. Moreover, paclitaxel-induced increase in the VDCC current in medium-diameter DRG neurons was completely inhibited by 10 and 100 μM gabapentin. Similar effects in small-diameter DRG neurons were only seen with 100 μM gabapentin. Western blotting revealed that paclitaxel increased protein levels of the VDCC subunit α2δ-1 (Cavα2δ-1) in DRG neurons. Immunohistochemistry showed that paclitaxel treatment increased Cavα2δ-1 protein expression in DRG neurons. Thus, paclitaxel treatment increases the VDCC current in small- and medium-diameter DRG neurons and upregulates Cavα2δ-1. The antihyperalgesic action of gabapentin may be due to inhibition of paclitaxel-induced increases in the VDCC current in DRG neurons.
    Download PDF (401K)
  • Da Hye Hong, Dongki Yang, Il-Whan Choi, Youn Kyoung Son, Won-Kyo Jung, ...
    2012 Volume 120 Issue 3 Pages 196-205
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 27, 2012
    JOURNALS FREE ACCESS
    We examined the effects of mibefradil, a T-type Ca2+ channel inhibitor, on voltage-dependent K+ (Kv) channels in rabbit coronary arterial smooth muscle cells using the whole-cell patch clamp technique. Mibefradil reduced the Kv current amplitude in a dose-dependent manner, with an apparent Kd value of 1.08 μM. Kv current inhibition by mibefradil was highly voltage-dependent over the full activation voltage range (−30 to +10 mV). The decay rate of Kv channel inactivation was accelerated by mibefradil without altering the kinetics of current activation. The rate constants of association and dissociation were 2.23 ± 0.07 μM−1·s−1 and 2.40 ± 0.42 s−1, respectively. Mibefradil had no significant effect on the steady-state activation or inactivation curves. In the presence of mibefradil, the recovery time constant from inactivation was decreased, and the application of train pulses (1 or 2 Hz) increased mibefradil-induced Kv channel inhibition, suggesting that the inhibitory effects of mibefradil were use-dependent. The inhibitory effect of mibefradil on Kv channels was unaffected by extracellular Ca2+-free conditions. Moreover, the absence of ATP inside the pipette did not alter the blocking effect of mibefradil. Therefore, we suggest that mibefradil directly inhibited the Kv current, independently of Ca2+ channel inhibition.
    Download PDF (482K)
  • Yukihiro Saito, Kazufumi Nakamura, Katsumasa Miyaji, Satoshi Akagi, Hi ...
    2012 Volume 120 Issue 3 Pages 206-212
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 30, 2012
    JOURNALS FREE ACCESS
    Acute vasoreactivity testing for patients with pulmonary arterial hypertension (PAH) has been reported to be useful to identify patients with sustained beneficial response to oral calcium-channel blockers (CCBs), but there is a risk of exacerbation during the testing with oral CCBs. Therefore, we developed a testing method utilizing intravenous nicardipine, a short-acting CCB, and examined the safety and usefulness of acute vasoreactivity testing with nicardipine in PAH patients. Acute vasoreactivity testing with nicardipine was performed in 65 PAH patients. Nicardipine was administered by short-time continuous infusion (1 μg·kg−1·min−1 for 5 min and 2 μg·kg−1·min−1 for 5 min) followed by bolus injection (5 μg/kg). Hemodynamic responses were continuously measured using a right heart catheter. Acute responders were defined as patients who showed a decrease in mean pulmonary artery pressure of at least 10 mmHg to an absolute level below 40 mmHg with preserved or increased cardiac output. Two acute responders and sixty-three non-acute responders were identified. There was no hemodynamic instability requiring additional inotropic agents or death during the testing. Acute responders had good responses to long-term oral CCBs. The acute vasoreactivity testing with nicardipine might be safe and useful for identifying CCB responders in PAH patients.
    Download PDF (513K)
  • Taku Nagai, Jinghua Yu, Yuko Kitahara, Toshitaka Nabeshima, Kiyofumi Y ...
    2012 Volume 120 Issue 3 Pages 213-227
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 26, 2012
    JOURNALS FREE ACCESS
    Polyriboinosinic-polyribocytidilic acid (polyI:C) is a synthetic analog that elicits viral-like immune responses in mammals. We have recently found that polyI:C treatment in neonatal mice induced abnormalities of emotional, cognitive, and sensorimotor gating and dysfunction of glutamatergic neurotransmission in adulthood. In this study, we investigated the effect of the NMDA-receptor co-agonist D-serine on polyI:C-induced behavioral abnormalities in mice. Neonatal ICR mice were repeatedly injected with polyI:C for 5 days from postnatal day 2 to 6. At 10 weeks, sensorimotor gating function was analyzed in the prepulse inhibition (PPI) test. Emotional function was analyzed in open field and social interaction tests. Cognitive function was analyzed by novel object recognition tests. D-Serine dose-dependently improved polyI:C-induced impairment of emotional and cognitive behaviors whereas it had no effect on PPI deficit in adults. The ameliorating effects of D-serine were antagonized by pretreatment with an NMDA-receptor antagonist, MK-801. Although the mRNA level of D-amino acid oxidase (DAAO) was increased in the prefrontal cortex and hippocampus of neonatal polyI:C-treated mice in adulthood, no changes were observed in D-serine content and DAAO enzymatic activity. These results suggest that D-serine ameliorates emotional and cognitive impairments of the polyI:C-treated mice through potentiating NMDA receptor activity.
    Download PDF (261K)
  • Tomoharu Yokoyama, Tadashi Tanoue, Erika Hasegawa, Yukio Ikeda, Shouic ...
    2012 Volume 120 Issue 3 Pages 228-240
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 26, 2012
    JOURNALS FREE ACCESS
    We examined the protective effects of the immunosuppressants cyclosporin A (CsA) and FK506 on abnormal cytosolic Ca2+ ([Ca2+]c) and mitochondrial Ca2+ concentration ([Ca2+]m) dynamics induced by ischemia or high L-glutamate concentration in mouse brain slice preparations. We used fura-4F and rhod-2 as indicators for [Ca2+]c and [Ca2+]m, respectively, in their acetoxymethylester form. Slice preparations loaded with either of these two indicators were exposed to ischemic artificial cerebrospinal fluid (oxygen- and glucose-deprived medium) for 12 min or to aerobic medium with high L-glutamate concentration (isotonic 20 mM L-glutamate) for 5 min. CsA (1 – 10 μM) showed significant protective effects on the maximum increase in ischemia-induced [Ca2+]c and [Ca2+]m. FK506 (10 μM) showed significant protective effects on the [Ca2+]m increase, but not on the ischemia-induced [Ca2+]c increase. Both immunosuppressants showed almost equal protective effects on the [Ca2+]c and [Ca2+]m increases induced by high L-glutamate concentration. These results suggest that the protective effects of CsA and FK506 on Ca2+ overloading may be dependent upon the common pharmacological sites of actions relating to their effects as immunosuppressants. The small, but significant depressant effects of these drugs could give us important clues for rescuing critical brain damage induced by Ca2+ overloading.
    Download PDF (1477K)
  • Chihiro Miyamoto, Yojiro Maehata, Shigeyuki Ozawa, Takeharu Ikoma, Eir ...
    2012 Volume 120 Issue 3 Pages 241-249
    Published: 2012
    Released: November 16, 2012
    [Advance publication] Released: October 26, 2012
    JOURNALS FREE ACCESS
    We previously reported that chemokine CXCL14/BRAK (BRAK) has antitumor activity in several carcinoma cells indicating that BRAK secretion suppresses carcinoma cells. Ras-homologous small GTPase (RhoA) and Rho-associated coiled-coil-containing protein kinase (ROCK) are important regulators of secretory processes, and activation of the RhoA/ROCK signaling pathway stimulates tumor invasion and metastasis. We investigated the effects of fasudil, a specific ROCK inhibitor, on BRAK secretion and tumor progression in mesenchymal fibrosarcoma cells (MC57). We demonstrated the antitumor activity of secreted BRAK using MC57 transplantation of BRAK in overexpressed transgenic mice. Further, to eliminate the influence of change in the mRNA expression of endogenous BRAK, we produced stable MC57 cell lines expressing BRAK (MC57-BRAK) or mock vector (MC57-MOCK). Fasudil significantly increased BRAK secretion by MC57-BRAK cells in a dose-dependent manner. To determine the effect of fasudil on tumor growth, MC57-BRAK and MC57-MOCK cells were transplanted into wild-type mice. Fasudil treatment suppressed tumor growth only in mice that had received MC57-BRAK cell transplants. These results indicate that fasudil inhibits fibrosarcoma growth by stimulating BRAK secretion and suggests that fasudil therapy might have clinical efficacy.
    Download PDF (371K)
Short Communication
feedback
Top