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Ganeyan A, Ganesh CB. Organization of enkephalinergic neuronal system in the central nervous system of the gecko Hemidactylus frenatus. Brain Struct Funct 2024:10.1007/s00429-024-02805-4. [PMID: 38713249 DOI: 10.1007/s00429-024-02805-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Accepted: 04/23/2024] [Indexed: 05/08/2024]
Abstract
Enkephalins are endogenous opioid pentapeptides that play a role in neurotransmission and pain modulation in vertebrates. However, the distribution pattern of enkephalinergic neurons in the brains of reptiles has been understudied. This study reports the organization of the methionine-enkephalin (M-ENK) and leucine-enkephalin (L-ENK) neuronal systems in the central nervous system of the gecko Hemidactylus frenatus using an immunofluorescence labeling method. Although M-ENK and L-ENK-immunoreactive (ir) fibers extended throughout the pallial and subpallial subdivisions, including the olfactory bulbs, M-ENK and L-ENK-ir cells were found only in the dorsal septal nucleus. Enkephalinergic perikarya and fibers were highly concentrated in the periventricular and lateral preoptic areas, as well as in the anterior and lateral subdivisions of the hypothalamus, while enkephalinergic innervation was observed in the hypothalamic periventricular nucleus, infundibular recess nucleus and median eminence. The dense accumulation of enkephalinergic content was noticed in the pars distalis of the hypophysis. In the thalamus, the nucleus rotundus and the dorsolateral, medial, and medial posterior thalamic nuclei contained M-ENK and L-ENK-ir fibers, whereas clusters of M-ENK and L-ENK-ir neurons were observed in the pretectum, mesencephalon, and rhombencephalon. The enkephalinergic fibers were also seen in the area X around the central canal, as well as the dorsal and ventral horns. The widespread distribution of enkephalin-containing neurons within the central nervous system implies that enkephalins regulate a variety of functions in the gecko, including sensory, behavioral, hypophysiotropic, and neuroendocrine functions.
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Affiliation(s)
- Ananya Ganeyan
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad, 580 003, India
| | - C B Ganesh
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad, 580 003, India.
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Ganeyan A, Ganesh CB. The opioid peptide leucine-enkephalin disrupts seasonal and gonadotropin-induced ovarian recrudescence in the gecko Hemidactylus frenatus. Comp Biochem Physiol A Mol Integr Physiol 2023; 283:111454. [PMID: 37263377 DOI: 10.1016/j.cbpa.2023.111454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/03/2023]
Abstract
The enkephalins are known to regulate many physiological functions, including reproduction in vertebrates. However, the role of leucine-enkephalin (L-ENK) in the ovarian recrudescence activity of reptiles is not known. In the present study, we studied the influence of L-ENK on seasonal and FSH-induced ovarian recrudescence during the breeding and non-breeding phases of the cycle in the tropical and subtropical gecko Hemidactylus frenatus. In the first experiment, treatment with 5 and 25 μg L-ENK resulted in a dose-dependent inhibitory effect on the hypothalamic gonadotropin-releasing hormone (GnRH) neurons and ovary, as indicated by a significantly decreased percent area of GnRH-immunoreactive (GnRH-ir) fibres in the median eminence and pars distalis of the pituitary gland, concomitant with complete absence of stage V (late vitellogenic) follicles in the ovary compared to those of experimental controls. In the second experiment, administration of FSH to lizards in the regression phase stimulated the recruitment of stage IV and V (vitellogenic) follicles in contrast to their absence in initial controls or treatment controls. However, similar treatment of FSH in combination with 25 μg L-ENK did not result in the development of stage IV or V follicles. Together, these results suggest for the first time that treatment with 5 and 25 μg L-ENK exerts a dose-dependent inhibitory effect on the hypothalamic GnRH release into the median eminence and pituitary gland, leading to the blockade of ovarian recrudescence. These results also suggest a possible direct inhibitory effect of L-ENK at the level of the ovary in the gecko.
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Affiliation(s)
- Ananya Ganeyan
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad 580 003, India
| | - C B Ganesh
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad 580 003, India.
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Sakharkar AJ, Ganesh CB. Leucine-enkephalin-immunoreactive neurons in the brain of the cichlid fish Oreochromis mossambicus. Neuropeptides 2020; 81:101999. [PMID: 31843219 DOI: 10.1016/j.npep.2019.101999] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/26/2019] [Accepted: 12/09/2019] [Indexed: 12/29/2022]
Abstract
Enkephalins are the pentapeptides involved in pain relief and neuroendocrine responses with high affinity for delta opioid receptors in vertebrates. In the present investigation, we studied the distribution of leucine-enkephalin-immunoreactive (L-ENK-ir) neurons in the brain of the cichlid fish Oreochromis mossambicus. Application of the antisera against L-ENK revealed the presence of numerous L-ENK-ir perikarya and fibres in subdivisions of the dorsal and the ventral telencephalon, the medial olfactory tract and the nucleus entopeduncularis, whereas intensely labelled L-ENK-ir fibres were noticed in the olfactory bulb. Furthermore, the presence of L-ENK-ir cells and dense accumulations of fibres in the preoptic area and its subdivisions, the nucleus preopticus pars magnocellularis and the nucleus preopticus pars parvocellularis suggested a role for this peptide in regulation of reproduction. While intensely labelled cells and fibres were found in the nucleus lateralis tuberis pars lateralis as well as the nucleus lateralis tuberis pars medialis, some L-ENK-ir fibres were seen at the hypothalamo-hypophyseal tract indicating the possible hypophysiotrophic role for this peptide. Numerous L-ENK-ir cells and dense network of fibres were observed in the subdivisions of the nucleus recess lateralis and the pretectal area, whereas intensely labelled thick network of L-ENK- fibres were found in the ventromedial thalamic nucleus, the sub-layers of the optic tectum and the rostral spinal cord. The widespread distribution of L-ENK-immunoreactivity in the olfactory bulb, the telencephalon, the diencephalon and the mesencephalon regions of the brain as well as the spinal cord suggests the possible involvement of this peptide in the regulation of diverse functions such as neuroendocrine, antinociceptive, visual and olfactory responses in O. mossambicus.
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Affiliation(s)
- Amul J Sakharkar
- Department of Biotechnology, Savitribai Phule Pune University, Pune 411007, India
| | - C B Ganesh
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad 580 003, India.
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Abstract
The pentapeptides methionine-enkephalin and leucine-enkephalin belong to the opioid family of peptides, and the non-opiate peptide adrenocorticotropin hormone (ACTH) to the melanocortin peptide family. Enkephalins/ACTH are derived from pro-enkephalin, pro-dynorphin or pro-opiomelanocortin precursors and, via opioid and melanocortin receptors, are responsible for many biological activities. Enkephalins exhibit the highest affinity for the δ receptor, followed by the μ and κ receptors, whereas ACTH binds to the five subtypes of melanocortin receptor, and is the only member of the melanocortin family of peptides that binds to the melanocortin-receptor 2 (ACTH receptor). Enkephalins/ACTH and their receptors exhibit a widespread anatomical distribution. Enkephalins are involved in analgesia, angiogenesis, blood pressure, embryonic development, emotional behavior, feeding, hypoxia, limbic system modulation, neuroprotection, peristalsis, and wound repair; as well as in hepatoprotective, motor, neuroendocrine and respiratory mechanisms. ACTH plays a role in acetylcholine release, aggressive behavior, blood pressure, bone maintenance, hyperalgesia, feeding, fever, grooming, learning, lipolysis, memory, nerve injury repair, neuroprotection, sexual behavior, sleep, social behavior, tissue growth and stimulates the synthesis and secretion of glucocorticoids. Enkephalins/ACTH are also involved in many pathologies. Enkephalins are implicated in alcoholism, cancer, colitis, depression, heart failure, Huntington's disease, influenza A virus infection, ischemia, multiple sclerosis, and stress. ACTH plays a role in Addison's disease, alcoholism, cancer, Cushing's disease, dermatitis, encephalitis, epilepsy, Graves' disease, Guillain-Barré syndrome, multiple sclerosis, podocytopathies, and stress. In this review, we provide an updated description of the enkephalinergic and ACTH systems.
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Affiliation(s)
- Ewing Duque-Díaz
- Universidad de Santander UDES, Laboratory of Neurosciences, School of Medicine, Bucaramanga, Colombia.
| | - Olga Alvarez-Ojeda
- Universidad Industrial de Santander, Department of Pathology, School of Medicine, Bucaramanga, Colombia
| | - Rafael Coveñas
- Laboratory of Neuroanatomy of the Peptidergic Systems, Institute of Neurosciences of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
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Wen DC, Hu XY, Wang YY, Luo JX, Lin W, Jia LY, Gong XY. Effects of aqueous extracts from Panax ginseng and Hippophae rhamnoides on acute alcohol intoxication: An experimental study using mouse model. J Ethnopharmacol 2016; 192:67-73. [PMID: 27374757 DOI: 10.1016/j.jep.2016.06.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 06/16/2016] [Accepted: 06/30/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Acute alcohol intoxication (AAI) is a frequent emergency, but therapeutic drugs with superior efficacy and safety are lacking. Panax ginseng (PG) and Hippophae rhamnoides (HR) respectively has a wide application as a complementary therapeutic agent in China for the treatment of AAI and liver injury induced by alcohol. We investigated the effects of aqueous extracts from PG and HR (AEPH) on AAI mice and identified its underlying mechanisms. MATERIALS AND METHODS Models of AAI were induced by intragastric administration of ethanol (8g/kg). Seventy-two Specific pathogen-free (SPF) male Kunming mice were randomly divided into six groups: normal group, positive control group, AEPH of low dosage (100mg/kg) group, AEPH of medium dose (200mg/kg) group, AEPH of high dosage (400mg/kg) group and model group. The mice were treated with metadoxine (MTD, 500mg/kg) and AEPH. Thirty minutes later, the normal group was given normal saline, while the other groups were given ethanol (i.g., 8g/kg). The impact of AEPH was observed. In the same way, another seventy-two Kunming mice were randomly divided into six groups equally. The blood ethanol concentration at 0.5, 1, 1.5, 2, 3 and 6h after ethanol intake was determined by way of gas chromatography. The activity of alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH) and microsomal ethanol oxidase (EO) in liver, and the concentration of β-endorphin (β-EP), leucine-enkephalin (LENK) in the brain were determined by enzyme-linked-immunosorbent serologic assay (ELISA). RESULTS AEPH markedly prolonged alcohol tolerance time and shortened sober-up time after acute ethanol administration. AEPH decreased blood ethanol levels in six tests after ethanol intake. The 7-day survival rate of AEPH group was obviously superior to model group. AEPH increased the activities of ADH, ALDH, and decreased EO activity in liver. The crucial find was that AEPH markedly decreased β-EP and LENK concentration in the brain. CONCLUSIONS AEPH can markedly increase the levels of ADH, ALDH, decrease EO activity in liver and decrease the concentration of β-EP and LENK in the brain to against acute alcohol intoxication in mice.
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Affiliation(s)
- Da-Chao Wen
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 610072, Sichuan Province, China; Department of Infectious Diseases, Teaching Hospital of Chengdu University of Traditional Chinese Medicine, 610072 Sichuan Province, China
| | - Xiao-Yu Hu
- Department of Infectious Diseases, Teaching Hospital of Chengdu University of Traditional Chinese Medicine, 610072 Sichuan Province, China.
| | - Yan-Yan Wang
- Department of Infectious Diseases, Teaching Hospital of Chengdu University of Traditional Chinese Medicine, 610072 Sichuan Province, China
| | - Jian-Xing Luo
- Department of Infectious Diseases, Teaching Hospital of Chengdu University of Traditional Chinese Medicine, 610072 Sichuan Province, China
| | - Wu Lin
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 610072, Sichuan Province, China
| | - Ling-Yan Jia
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 610072, Sichuan Province, China
| | - Xin-Yue Gong
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 610072, Sichuan Province, China
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Yang DJ, Lee KS, Ko CM, Moh SH, Song J, Hur LC, Cheon YW, Yang SH, Choi YH, Kim KW. Leucine-enkephalin promotes wound repair through the regulation of hemidesmosome dynamics and matrix metalloprotease. Peptides 2016; 76:57-64. [PMID: 26763532 DOI: 10.1016/j.peptides.2015.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/03/2015] [Accepted: 12/29/2015] [Indexed: 11/17/2022]
Abstract
The skin responds to environmental stressors by coordinated actions of neuropeptides and their receptors. An endogenous peptide for δ-opioid receptor (DOPr), Leu-enkephalin (L-ENK), is expressed in the skin and its expression is altered in pathological conditions. Although the importance of DOPr is rapidly gaining recognition, the molecular mechanisms underlying its effects on wound healing are largely undefined. We show here that L-ENK induced activation of Erk, P90(RSK), and Elk-1 and promoted the disruption of hemidesmosomes and the expression of matrix metalloprotease (MMP)-2 and MMP-9, important processes for wound healing. Treatment with Erk inhibitor blocked activation of P90(RSK) and Elk-1 and significantly blunted wound repair. Therefore, our results suggest that activation of Erk and its downstream effectors, P90(RSK) and Elk-1, are critical for DOPr-mediated skin homeostasis.
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Affiliation(s)
- Dong Joo Yang
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea; Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea
| | - Kyung Suk Lee
- Department of Plastic and Reconstructive Surgery, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju 52828, Republic of Korea
| | - Chang Mann Ko
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea
| | - Sang Hyun Moh
- Anti-aging Research Institute of BIO-FD&C Co. Ltd., Incheon 21990, Republic of Korea
| | - Jihyeok Song
- Anti-aging Research Institute of BIO-FD&C Co. Ltd., Incheon 21990, Republic of Korea
| | - Lucia C Hur
- Derma-Lucia Skinceuticals LLC, 7500 Escala Drive, Austin, TX 78735, USA
| | - Young Woo Cheon
- Department of Plastic and Reconstructive Surgery, Gachon University Gil Medical Center, Gachon University, School of Medicine, 1198 Guwol-Dong, Namdong-Gu, Incheon 21565, Republic of Korea
| | - Seung Ho Yang
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea
| | - Yun-Hee Choi
- Anti-aging Research Institute of BIO-FD&C Co. Ltd., Incheon 21990, Republic of Korea.
| | - Ki Woo Kim
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea; Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju 26426, Republic of Korea.
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Komatsu T, Katsuyama S, Mizoguchi H, Sakurada C, Tsuzuki M, Sakurada S, Sakurada T. Spinal ERK2 activation through δ2-opioid receptors contributes to nociceptive behavior induced by intrathecal injection of leucine-enkephalin. Peptides 2014; 54:131-9. [PMID: 24480726 DOI: 10.1016/j.peptides.2014.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/07/2014] [Accepted: 01/08/2014] [Indexed: 11/15/2022]
Abstract
Intrathecal (i.t.) injection of leucine-enkephalin (Leu-ENK), co-administered with peptidase inhibitors, phosphoramidon (an endopeptidase 24.11 inhibitor), and bestatin (a general aminopeptidase inhibitor), produced behaviors consisting of the biting and/or licking of the hindpaw and the tail along with hindlimb scratching directed toward the flank, which peaked at 10-15 min after an injection. This characteristic behavior was not observed in mice treated with i.t. Leu-ENK alone. We also investigated the effect of the extracellular signal-regulated kinase (ERK) in spinal processing of nociception induced by i.t. co-administration of Leu-ENK with phospharamidon and bestatin. Western blot analysis of phospho-ERK (pERK) showed a significant increase of pERK2 in the lumbar spinal cord in response to i.t. Leu-ENK co-injected with peptidase inhibitors. The MAP kinase-ERK inhibitor, U0126 dose-dependently attenuated the nociceptive behavior and spinal ERK activation to i.t. Leu-ENK co-injected with peptidase inhibitors. Furthermore, the nociceptive behavior and spinal ERK activation evoked by i.t. Leu-ENK in combination with peptidase inhibitors were inhibited by co-administration of the non-selective δ-opioid receptor antagonist, naltrindole, the selective δ2-opioid receptor antagonist, naltriben, the non-competitive N-methyl-D-aspartate (NMDA) antagonist, MK-801 or the non-selective nitric oxide synthase inhibitor, L-NAME, the selective nNOS inhibitor, N(ω)-propyl-L-arginine or the selective iNOS inhibitor, W1400, but not by the selective δ1-receptor antagonist, BNTX (7-benzylidenenaltrexone). These results suggest that spontaneous nociceptive behaviors produced by i.t. co-administration of Leu-ENK with peptidase inhibitors may be induced by an activation of the glutamate-NO-ERK pathway through the δ2-opioid receptor in the dorsal spinal cord.
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MESH Headings
- Animals
- Arginine/analogs & derivatives
- Arginine/pharmacology
- Behavior, Animal/drug effects
- Butadienes/pharmacology
- Enkephalin, Leucine/administration & dosage
- Enkephalin, Leucine/pharmacology
- Enzyme Activation/drug effects
- Glycopeptides/pharmacology
- Injections, Spinal
- Leucine/analogs & derivatives
- Leucine/pharmacology
- Male
- Mice, Inbred Strains
- Mitogen-Activated Protein Kinase 1/metabolism
- NG-Nitroarginine Methyl Ester/pharmacology
- Naltrexone/analogs & derivatives
- Naltrexone/pharmacology
- Nitric Oxide Synthase/antagonists & inhibitors
- Nitriles/pharmacology
- Nociception/drug effects
- Protease Inhibitors/pharmacology
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/metabolism
- Spinal Cord/drug effects
- Spinal Cord/metabolism
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Affiliation(s)
- Takaaki Komatsu
- Department of Pharmacology, Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan
| | - Soh Katsuyama
- Department of Clinical Pharmaceutics, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
| | - Hirokazu Mizoguchi
- Department of Physiology and Anatomy, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
| | - Chikai Sakurada
- Department of Biochemistry, Nihon Pharmaceutical University, 10281 Komuro, Ina-Machi, Kitaadachi-gun, Saitama 362-0806, Japan
| | - Minoru Tsuzuki
- Department of Biochemistry, Nihon Pharmaceutical University, 10281 Komuro, Ina-Machi, Kitaadachi-gun, Saitama 362-0806, Japan
| | - Shinobu Sakurada
- Department of Physiology and Anatomy, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
| | - Tsukasa Sakurada
- Department of Pharmacology, Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan.
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