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Aoki R, Yagami T, Sasakura H, Ogura KI, Kajihara Y, Ibi M, Miyamae T, Nakamura F, Asakura T, Kanai Y, Misu Y, Iino Y, Ezcurra M, Schafer WR, Mori I, Goshima Y. A seven-transmembrane receptor that mediates avoidance response to dihydrocaffeic acid, a water-soluble repellent in Caenorhabditis elegans. J Neurosci 2011; 31:16603-10. [PMID: 22090488 PMCID: PMC6633322 DOI: 10.1523/jneurosci.4018-11.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 10/03/2011] [Accepted: 10/04/2011] [Indexed: 11/21/2022] Open
Abstract
The ability to detect harmful chemicals rapidly is essential for the survival of all animals. In Caenorhabditis elegans (C. elegans), repellents trigger an avoidance response, causing animals to move away from repellents. Dihydrocaffeic acid (DHCA) is a water-soluble repellent and nonflavonoid catecholic compound that can be found in plant products. Using a Xenopus laevis (X. laevis) oocyte expression system, we identified a candidate dihydrocaffeic acid receptor (DCAR), DCAR-1. DCAR-1 is a novel seven-transmembrane protein that is expressed in the ASH avoidance sensory neurons of C. elegans. dcar-1 mutant animals are defective in avoidance response to DHCA, and cell-specific expression of dcar-1 in the ASH neurons of dcar-1 mutant animals rescued the defect in avoidance response to DHCA. Our findings identify DCAR-1 as the first seven-transmembrane receptor required for avoidance of a water-soluble repellent, DHCA, in C. elegans.
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Affiliation(s)
- Reina Aoki
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Tatsurou Yagami
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
- Department of Physiology, Himeji Dokkyo University, Himeji 670-8524, Japan
| | - Hiroyuki Sasakura
- Department of Molecular Biology, Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Ken-ichi Ogura
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Yasuhiro Kajihara
- Department of Chemistry Graduate School of Science, Osaka University, Osaka, 560-0043, Japan
| | - Masakazu Ibi
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
- Department of Pharmacology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Takeaki Miyamae
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Fumio Nakamura
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Taro Asakura
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Yoshikatsu Kanai
- Department of Pharmacology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Yoshimi Misu
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Yuichi Iino
- Molecular Genetics Research Laboratory and Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Marina Ezcurra
- Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom, and
- Department of Biosciences and Nutrition, Karolinska Institute, S-14157 Huddinge, Sweden
| | - William R. Schafer
- Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom, and
| | - Ikue Mori
- Department of Molecular Biology, Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Yoshio Goshima
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University, Graduate School of Medicine, Yokohama 236-0004, Japan
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Misu Y, Kitahama K, Goshima Y. L-3,4-Dihydroxyphenylalanine as a neurotransmitter candidate in the central nervous system. Pharmacol Ther 2003; 97:117-37. [PMID: 12559386 DOI: 10.1016/s0163-7258(02)00325-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Historically, 3,4-dihydroxyphenylalanine (DOPA) has been believed to be an inert amino acid that alleviates the symptoms of Parkinson's disease by its conversion to dopamine via the enzyme aromatic L-amino acid decarboxylase. In contrast to this generally accepted idea, we propose that DOPA itself is a neurotransmitter and/or neuromodulator, in addition to being a precursor of dopamine. Several criteria, such as synthesis, metabolism, active transport, existence, physiological release, competitive antagonism, and physiological or pharmacological responses, must be satisfied before a compound is accepted as a neurotransmitter. Recent evidence suggests that DOPA fulfills these criteria in its involvement mainly in baroreflex neurotransmission in the lower brainstem and in delayed neuronal death by transient ischemia in the striatum and the hippocampal CA1 region of rats.
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Affiliation(s)
- Yoshimi Misu
- Department of Pharmacology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
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Miyamae T, Goshima Y, Shimizu M, Shibata T, Kawashima K, Ohshima E, Suzuki F, Misu Y. Some interactions of L-DOPA and its related compounds with glutamate receptors. Life Sci 1999; 64:1045-54. [PMID: 10210287 DOI: 10.1016/s0024-3205(99)00031-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
L-DOPA is probably a transmitter and/or modulator in the central nervous system (1). L-DOPA methyl ester (DOPA ME) is a competitive L-DOPA antagonist. However, it remains to be clarified whether there exist L-DOPAergic receptors. In Xenopus laevis oocytes injected with rat brain poly(A)+ RNA, L-DOPA induced small inward currents with ED50 of 2.2 mM at a holding potential of -70 mV. The currents were abolished by kynurenic acid or CNQX. Similar L-DOPA-currents were seen in oocytes co-injected with AMPA receptors, GluRs1,2,3 and 4. In brain membrane preparations, L-DOPA inhibited specific binding of [3H]-AMPA with IC50 of 260 microM. This inhibition was not modified by 200 microM ascorbic acid, an antioxidant. L-DOPA did not inhibit binding of [3H]-ligands of MK-801, kainate, DCKA and CGP39653. DOPA ME and L-DOPA cyclohexyl ester, a novel, potent and competitive antagonist (2), inhibited specific binding of [3H]-MK-801 with respective IC50 of 1 and 0.68 mM, but elicited no effect on that of the other [3H]-ligands. With low affinities, L-DOPA acts on AMPA receptors, while competitive antagonists act on NMDA ion channel domain. L-DOPAergic agonist and antagonist may not interact on ionotropic glutamate receptors. DOPA ME-sensitive L-DOPA recognition sites (1) seem to differ from glutamate receptors.
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Affiliation(s)
- T Miyamae
- Department of Pharmacology, Yokohama City University School of Medicine, Yokohama, Japan
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Furukawa N, Goshima Y, Miyamae T, Nishihama M, Okumura F, Fujita K, Misu Y. An L-DOPA-like depressor action of L-threo-dihydroxyphenyl-serine in the rat caudal ventrolateral medulla. Life Sci 1997; 61:1177-83. [PMID: 9315508 DOI: 10.1016/s0024-3205(97)00659-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have proposed that L-3,4-dihydroxyphenylalanine (L-DOPA) is a neurotransmitter and/or neuromodulator in the central nervous system (1). In this study, we investigated whether or not L-threo-dihydroxyphenylserine (L-threo-DOPS), a synthetic amino acid structurally related to L-DOPA, microinjected into the caudal ventrolateral medulla (CVLM) and the rostral ventrolateral medulla (RVLM) shows cardiovascular actions similar to those of L-DOPA in anesthetized rats. When L-threo-DOPS was microinjected into CVLM, it produced dose-dependent (0.01-3 ng) depressor and bradycardic responses. D-threo-DOPS (3 ng) produced no effect. The responses to L-threo-DOPS (1 ng) were almost completely blocked by L-DOPA methyl ester (1 microg), a competitive antagonist for L-DOPA, supporting the existence of an L-threo-DOPS-sensitive recognition site for L-DOPA in CVLM. Microinjection of L-threo-DOPS into RVLM, however, showed no effect (0.001-100 ng), which contrasted with the cardiopressor action of L-DOPA applied in RVLM. In RVLM, there may exist an L-threo-DOPS-insensitive recognition site for L-DOPA.
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Affiliation(s)
- N Furukawa
- Department of Pharmacology, Yokohama City University School of Medicine, Yokohama, Japan
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Abstract
L-DOPA is proposed to be a neurotransmitter and/or neuromodulator in CNS. It is released probably from neurons, which may contain L-DOPA as an end-product, and/or from some compartment other than catecholamine-containing vesicles. The L-DOPA itself produces presynaptic and postsynaptic responses. All are stereoselective and most are antagonized by competitive antagonist. In striatum, L-DOPA is neuromodulator, mother of catecholamines, not only a precursor for dopamine but also a potentiator of children for presynaptic beta-adrenoceptors to facilitate dopamine release and postsynaptic D2 receptors, and ACh release inhibitor. All may cooperate for Parkinson's disease. Meanwhile, supersensitization of increase in L-glutamate release to nanomolar levodopa was seen in Parkinson's model rats, which may relate to dyskinesia or "on-off" during chronic therapy. In lower brainstem, L-DOPA tonically activates postsynaptic depressor sites of NTS and CVLM and pressor sites of RVLM. L-DOPA is probably a neurotransmitter of primary baroreceptor afferents terminating in NTS. GABA, the inhibitory neuromodulator for baroreflex in NTS, tonically functions to inhibit, via GABAA receptors, L-DOPA release and depressor responses to levodopa. Levodopa inversely releases GABA. L-DOPAergic monosynaptic relay from NTS to CVLM and from PHN to RVLM is suggested. Tonic L-DOPAergic baroreceptor-aortic nerve-NTS-CVLM relay seems to carry baroreflex information. Disturbance of neuronal activity to release L-DOPA in NTS, loss of the activity in CVLM, enhancement of the activity with decreased decarboxylation and increase in sensitivity to levodopa in RVLM may be involved in maintenance of hypertension in SHR. This is a story of "L-DOPAergic receptors" with extremely high affinity and low density.
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Affiliation(s)
- Y Misu
- Department of Pharmacology, Yokohama City University School of Medicine, Japan
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