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Caragea VM, Méndez-Couz M, Manahan-Vaughan D. Dopamine receptors of the rodent fastigial nucleus support skilled reaching for goal-directed action. Brain Struct Funct 2024; 229:609-637. [PMID: 37615757 PMCID: PMC10978667 DOI: 10.1007/s00429-023-02685-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 07/07/2023] [Indexed: 08/25/2023]
Abstract
The dopaminergic (DA) system regulates both motor function, and learning and memory. The cerebellum supports motor control and the acquisition of procedural memories, including goal-directed behavior, and is subjected to DA control. Its fastigial nucleus (FN) controls and interprets body motion through space. The expression of dopamine receptors has been reported in the deep cerebellar nuclei of mice. However, the presence of dopamine D1-like (D1R) and D2-like (D2R) receptors in the rat FN has not yet been verified. In this study, we first confirmed that DA receptors are expressed in the FN of adult rats and then targeted these receptors to explore to what extent the FN modulates goal-directed behavior. Immunohistochemical assessment revealed expression of both D1R and D2R receptors in the FN, whereby the medial lateral FN exhibited higher receptor expression compared to the other FN subfields. Bilateral treatment of the FN with a D1R antagonist, prior to a goal-directed pellet-reaching task, significantly impaired task acquisition and decreased task engagement. D2R antagonism only reduced late performance post-acquisition. Once task acquisition had occurred, D1R antagonism had no effect on successful reaching, although it significantly decreased reaching speed, task engagement, and promoted errors. Motor coordination and ambulation were, however, unaffected as neither D1R nor D2R antagonism altered rotarod latencies or distance and velocity in an open field. Taken together, these results not only reveal a novel role for the FN in goal-directed skilled reaching, but also show that D1R expressed in FN regulate this process by modulating motivation for action.
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Affiliation(s)
- Violeta-Maria Caragea
- Department of Neurophysiology, Faculty of Medicine, Ruhr-University Bochum, Universitätsstr. 150, MA 4/150, 44780, Bochum, Germany
| | - Marta Méndez-Couz
- Department of Neurophysiology, Faculty of Medicine, Ruhr-University Bochum, Universitätsstr. 150, MA 4/150, 44780, Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Faculty of Medicine, Ruhr-University Bochum, Universitätsstr. 150, MA 4/150, 44780, Bochum, Germany.
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2
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Li C, Saliba NB, Martin H, Losurdo NA, Kolahdouzan K, Siddiqui R, Medeiros D, Li W. Purkinje cell dopaminergic inputs to astrocytes regulate cerebellar-dependent behavior. Nat Commun 2023; 14:1613. [PMID: 36959176 PMCID: PMC10036610 DOI: 10.1038/s41467-023-37319-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 03/13/2023] [Indexed: 03/25/2023] Open
Abstract
Dopamine has a significant role in motor and cognitive function. The dopaminergic pathways originating from the midbrain have received the most attention; however, the relevance of the cerebellar dopaminergic system is largely undiscovered. Here, we show that the major cerebellar astrocyte type Bergmann glial cells express D1 receptors. Dopamine can be synthesized in Purkinje cells by cytochrome P450 and released in an activity-dependent fashion. We demonstrate that activation of D1 receptors induces membrane depolarization and Ca2+ release from the internal store. These astrocytic activities in turn modify Purkinje cell output by altering its excitatory and inhibitory synaptic input. Lastly, we show that conditional knockout of D1 receptors in Bergmann glial cells results in decreased locomotor activity and impaired social activity. These results contribute to the understanding of the molecular, cellular, and circuit mechanisms underlying dopamine function in the cerebellum, revealing a critical role for the cerebellar dopaminergic system in motor and social behavior.
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Affiliation(s)
- Chang Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Natalie B Saliba
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hannah Martin
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
| | - Nicole A Losurdo
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Neuroscience Program, The University of Utah, Salt Lake City, UT, USA
| | - Kian Kolahdouzan
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Riyan Siddiqui
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Destynie Medeiros
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Wei Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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3
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Flace P, Livrea P, Basile GA, Galletta D, Bizzoca A, Gennarini G, Bertino S, Branca JJV, Gulisano M, Bianconi S, Bramanti A, Anastasi G. The Cerebellar Dopaminergic System. Front Syst Neurosci 2021; 15:650614. [PMID: 34421548 PMCID: PMC8375553 DOI: 10.3389/fnsys.2021.650614] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/04/2021] [Indexed: 12/04/2022] Open
Abstract
In the central nervous system (CNS), dopamine (DA) is involved in motor and cognitive functions. Although the cerebellum is not been considered an elective dopaminergic region, studies attributed to it a critical role in dopamine deficit-related neurological and psychiatric disorders [e.g., Parkinson's disease (PD) and schizophrenia (SCZ)]. Data on the cerebellar dopaminergic neuronal system are still lacking. Nevertheless, biochemical studies detected in the mammalians cerebellum high dopamine levels, while chemical neuroanatomy studies revealed the presence of midbrain dopaminergic afferents to the cerebellum as well as wide distribution of the dopaminergic receptor subtypes (DRD1-DRD5). The present review summarizes the data on the cerebellar dopaminergic system including its involvement in associative and projective circuits. Furthermore, this study also briefly discusses the role of the cerebellar dopaminergic system in some neurologic and psychiatric disorders and suggests its potential involvement as a target in pharmacologic and non-pharmacologic treatments.
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Affiliation(s)
- Paolo Flace
- Medical School, University of Bari ‘Aldo Moro', Bari, Italy
| | | | - Gianpaolo Antonio Basile
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Diana Galletta
- Unit of Psychiatry and Psychology, Federico II University Hospital, Naples, Italy
| | - Antonella Bizzoca
- Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari “Aldo Moro”, Bari, Italy
| | - Gianfranco Gennarini
- Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari “Aldo Moro”, Bari, Italy
| | - Salvatore Bertino
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | | | - Massimo Gulisano
- Department of Experimental and Clinical Medicine, University of Firenze, Firenze, Italy
| | - Simona Bianconi
- Physical, Rehabilitation Medicine and Sport Medicine Unit, University Hospital “G. Martino”, Messina, Italy
| | - Alessia Bramanti
- Scientific Institute for Research, Hospitalization and Health Care IRCCS “Centro Neurolesi Bonino Pulejo”, Messina, Italy
| | - Giuseppe Anastasi
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
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4
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de Oliveira PG, Ramos MLS, Amaro AJ, Dias RA, Vieira SI. G i/o-Protein Coupled Receptors in the Aging Brain. Front Aging Neurosci 2019; 11:89. [PMID: 31105551 PMCID: PMC6492497 DOI: 10.3389/fnagi.2019.00089] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/03/2019] [Indexed: 12/18/2022] Open
Abstract
Cells translate extracellular signals to regulate processes such as differentiation, metabolism and proliferation, via transmembranar receptors. G protein-coupled receptors (GPCRs) belong to the largest family of transmembrane receptors, with over 800 members in the human species. Given the variety of key physiological functions regulated by GPCRs, these are main targets of existing drugs. During normal aging, alterations in the expression and activity of GPCRs have been observed. The central nervous system (CNS) is particularly affected by these alterations, which results in decreased brain functions, impaired neuroregeneration, and increased vulnerability to neuropathologies, such as Alzheimer's and Parkinson diseases. GPCRs signal via heterotrimeric G proteins, such as Go, the most abundant heterotrimeric G protein in CNS. We here review age-induced effects of GPCR signaling via the Gi/o subfamily at the CNS. During the aging process, a reduction in protein density is observed for almost half of the Gi/o-coupled GPCRs, particularly in age-vulnerable regions such as the frontal cortex, hippocampus, substantia nigra and striatum. Gi/o levels also tend to decrease with aging, particularly in regions such as the frontal cortex. Alterations in the expression and activity of GPCRs and coupled G proteins result from altered proteostasis, peroxidation of membranar lipids and age-associated neuronal degeneration and death, and have impact on aging hallmarks and age-related neuropathologies. Further, due to oligomerization of GPCRs at the membrane and their cooperative signaling, down-regulation of a specific Gi/o-coupled GPCR may affect signaling and drug targeting of other types/subtypes of GPCRs with which it dimerizes. Gi/o-coupled GPCRs receptorsomes are thus the focus of more effective therapeutic drugs aiming to prevent or revert the decline in brain functions and increased risk of neuropathologies at advanced ages.
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Affiliation(s)
- Patrícia G de Oliveira
- Department of Medical Sciences, Institute of Biomedicine (iBiMED) and The Discovery CTR, Universidade de Aveiro, Aveiro, Portugal
| | - Marta L S Ramos
- Department of Medical Sciences, Institute of Biomedicine (iBiMED) and The Discovery CTR, Universidade de Aveiro, Aveiro, Portugal
| | - António J Amaro
- School of Health Sciences (ESSUA), Universidade de Aveiro, Aveiro, Portugal
| | - Roberto A Dias
- Department of Medical Sciences, Institute of Biomedicine (iBiMED) and The Discovery CTR, Universidade de Aveiro, Aveiro, Portugal
| | - Sandra I Vieira
- Department of Medical Sciences, Institute of Biomedicine (iBiMED) and The Discovery CTR, Universidade de Aveiro, Aveiro, Portugal
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5
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Beneficial behavioral, neurochemical and molecular effects of 1-(R)-aminoindan in aged mice. Neuropharmacology 2015; 99:264-72. [DOI: 10.1016/j.neuropharm.2015.05.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 05/26/2015] [Accepted: 05/28/2015] [Indexed: 11/19/2022]
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6
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Nakajima S, Caravaggio F, Boileau I, Chung JK, Plitman E, Gerretsen P, Wilson AA, Houle S, Mamo DC, Graff-Guerrero A. Lack of age-dependent decrease in dopamine D3 receptor availability: a [(11)C]-(+)-PHNO and [(11)C]-raclopride positron emission tomography study. J Cereb Blood Flow Metab 2015; 35:1812-8. [PMID: 26058690 PMCID: PMC4635236 DOI: 10.1038/jcbfm.2015.129] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/17/2015] [Accepted: 04/23/2015] [Indexed: 02/05/2023]
Abstract
Positron emission tomography with antagonist radiotracers has showed that striatal dopamine D2/3 receptor (D2/3R) availability decreases with age. However, no study has specifically assessed whether D2/3R availability decreases with age in healthy persons as measured with agonist radiotracers. Moreover, it is unknown whether D3R availability changes with age in healthy humans. Thus, we explored the relationship between age and D2/3R availability in healthy humans using the D3 receptor (D3R)-preferential agonist radiotracer [(11)C]-(+)-PHNO (n=72, mean±s.d. age=40±15, range=18 to 73) and the antagonist [(11)C]-Raclopride (n=70, mean±s.d. age =40±14, range=18 to 73) (both, n=33). The contribution of D3R to the [(11)C]-(+)-PHNO signal varies across regions of interest; the substantia nigra and hypothalamus represent D3R-specific regions, the ventral pallidum, globus pallidus, and ventral striatum represent D2/3R-mixed regions, and the caudate and putamen represent D2 receptor (D2R)-specific regions. With [(11)C]-(+)-PHNO, a negative correlation was observed between age and nondisplaceable binding potential (BPND) in the caudate (r(70)=-0.32, P=0.005). No correlations were observed in the other regions. With [(11)C]-Raclopride, negative correlations were observed between age and BPND in the caudate (r(68)=-0.50, P<0.001), putamen (r(68)=-0.41, P<0.001), and ventral striatum (r(68)=-0.43, P<0.001). In conclusion, in contrast with the age-dependent decrease in D2R availability, these findings suggest that D3R availability does not change with age.
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Affiliation(s)
- Shinichiro Nakajima
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan
| | - Fernando Caravaggio
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Isabelle Boileau
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Campbell Research Institute, Toronto, Ontario, Canada
| | - Jun K Chung
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Eric Plitman
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Philip Gerretsen
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Alan A Wilson
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Campbell Research Institute, Toronto, Ontario, Canada
| | - Sylvain Houle
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Campbell Research Institute, Toronto, Ontario, Canada
| | - David C Mamo
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Department of Psychiatry, University of Malta, Valletta, Malta
| | - Ariel Graff-Guerrero
- Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health, Campbell Research Institute, Toronto, Ontario, Canada
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7
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Rani M, Kanungo MS. Expression of D2 dopamine receptor in the mouse brain. Biochem Biophys Res Commun 2006; 344:981-6. [PMID: 16643854 DOI: 10.1016/j.bbrc.2006.03.075] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Accepted: 03/13/2006] [Indexed: 10/24/2022]
Abstract
The neurotransmitter, dopamine, binds to dopamine receptor (DR), and is involved in several functions of the brain, such as initiation and execution of movement, emotion, prolactin secretion, etc. Of all the five DRs, D2 dopamine receptor has maximal affinity for dopamine. D2 has a short isoform, D2S, and a long isoform D2L. D2L is longer than D2S by 29 amino acid residues. We studied the expression of the gene and protein of D2 receptor in the cerebral and cerebellar cortices of the brain of new born, developing, adult, and old male mice to find out: (i) at what stage of development, expression of the gene peaks and (ii) if it undergoes any changes as the animal ages, which may account for the neurodegenerative changes and symptoms of Parkinson's and other diseases seen in old age. RT-PCR and Western blot studies show that peak expression of D2 gene occurs in the cerebral and cerebellar cortices around 15-day after birth. We speculate that the majority of dopaminergic synapses are established and possibly become functional in the brain around 15-day after birth. The expression of D2 receptor is upregulated in the cerebral cortex in old mice. However, it is down-regulated in the cerebellar cortex.
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Affiliation(s)
- Manjusha Rani
- Molecular Biology Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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8
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Amenta F, Mignini F, Ricci A, Sabbatini M, Tomassoni D, Tayebati SK. Age-related changes of dopamine receptors in the rat hippocampus: a light microscope autoradiography study. Mech Ageing Dev 2001; 122:2071-83. [PMID: 11589924 DOI: 10.1016/s0047-6374(01)00317-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Hippocampus is a brain region involved in learning and memory and is particularly sensitive to ageing. It is supplied with a dopaminergic innervation arising from the midbrain, which is part of the mesolimbic dopaminergic pathway. Dysfunction of the dopaminergic mesolimbic system is probably involved in the pathophysiology of psychosis and behavioural disturbances occurring in the elderly. The present study was designed to assess the density and localisation of dopamine D1- and D2-like receptor subtypes in the hippocampus of male Sprague-Dawley rats aged 3 months (young), 12 months (adult) and 24 months (old). Dopamine D1-like receptors, labelled by [3H]-SCH 23390, in young rats displayed a dentate gyrus-CA1 subfield gradient. The expression was increased in the cell body of dentate gyrus, CA4 and CA3 subfield of old rats compared to younger cohorts, as well as in the neuropil of dentate gyrus. A decreased density of dopamine D1-like receptors was found in the stratum oriens of CA1 and CA3 subfields. Dopamine D2-like receptors, labelled using [3H]-spiperone as radioligand, were expressed rather homogeneously throughout different subfields of the hippocampus. In old rats, the density of dopamine D2-like receptors was decreased in the dentate gyrus, unchanged in the CA4 and CA1 subfields and increased in the CA3 subfield. The above results indicate the occurrence of inhomogeneous changes in the density of dopamine D1- and D2-like receptors in specific portions of hippocampus of old rats. These findings support the hypothesis of an involvement of dopaminergic system in behavioural abnormalities or psychosis occurring in ageing.
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Affiliation(s)
- F Amenta
- Sezione di Anatomia Umana, Dipartimento di Scienze Farmacologiche e Medicina Sperimentale, Università di Camerino, Via Scalzino, 3, 62032, Camerino, Italy.
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9
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Blanton CA, Horwitz BA, Blevins JE, Hamilton JS, Hernandez EJ, McDonald RB. Reduced feeding response to neuropeptide Y in senescent Fischer 344 rats. Am J Physiol Regul Integr Comp Physiol 2001; 280:R1052-60. [PMID: 11247827 DOI: 10.1152/ajpregu.2001.280.4.r1052] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The anorexia of aging syndrome in humans is characterized by spontaneous body weight loss reflecting diminished food intake. We reported previously that old rats undergoing a similar phenomenon of progressive weight loss (i.e., senescent rats) also display altered feeding behavior, including reduced meal size and duration. Here, we tested the hypothesis that blunted responsiveness to neuropeptide Y (NPY), a feeding stimulant, occurs concurrently with senescence-associated anorexia/hypophagia. Young (8 mo old, n = 9) and old (24-30 mo old, n = 11) male Fischer 344 rats received intracerebroventricular NPY or artificial cerbrospinal fluid injections. In response to a maximum effective NPY dose (10 microg), the net increase in size of the first meal after injection was similar in old weight-stable (presenescent) and young rats (10.85 +/- 1.73 and 12.63 +/- 2.52 g/kg body wt (0.67), respectively). In contrast, senescent rats that had spontaneously lost approximately 10% of body weight had significantly lower net increases at their first post-NPY meal (1.33 +/- 0.33 g/kg body wt (0.67)) than before they began losing weight. Thus altered feeding responses to NPY occur in aging rats concomitantly with spontaneous decrements in food intake and body weight near the end of life.
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Affiliation(s)
- C A Blanton
- Department of Nutrition, Section of Neurobiology, Physiology, and Behavior, University of California, 1 Shields Ave., Davis, CA 95616, USA
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Barili P, Bronzetti E, Ricci A, Zaccheo D, Amenta F. Microanatomical localization of dopamine receptor protein immunoreactivity in the rat cerebellar cortex. Brain Res 2000; 854:130-8. [PMID: 10784114 DOI: 10.1016/s0006-8993(99)02306-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dopamine (DA) receptor subtype localization was investigated in rat cerebellar cortex using immunohistochemical techniques with antibodies raised against D1-D5 receptor protein. A faint D1 receptor protein immunoreactivity was developed in molecular and Purkinje neurons layers. D2 receptor protein immunoreactivity was found primarily in cerebellar white matter followed by molecular and granular layers and Purkinje neurons. Antibodies against D2S receptor protein were localized in molecular layer and to a lesser extent, in granular layer. A few Purkinje neurons displayed a faint D2S receptor protein immunoreactivity. D3 receptor protein immunoreactivity was observed primarily in molecular and in Purkinje neurons layers of lobules 9 and 10. A faint D3 receptor protein immunoreactivity was also localized in Purkinje neurons and to a lesser extent, in molecular and granular layers of cerebellar lobules 1-8. D4 receptor protein immunoreactivity was found in cerebellar white matter. A pale immunostaining was also visualized in molecular layer. D5 receptor protein immunoreactivity was localized primarily in molecular and Purkinje neurons layers and to a lesser extent, in granular layer and in white matter. The above results indicate that rat cerebellar cortex expresses the DA receptor subtypes so far identified. Purkinje neurons, which are the only efferent neurons of cerebellum, are richest in DA receptor protein immunoreactivity. This suggests that dopaminergic neurotransmission may modulate efferent inputs from cerebellum. The localization of the majority of D2 and D4 and of a faint D5 protein receptor immunoreactivity in cerebellar white matter suggests that these receptors may be presynaptic and transported axonally.
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Affiliation(s)
- P Barili
- Sezione di Anatomia Umana, Dipartimento di Scienze Farmacologiche e Medicina Spermentale, Università di Camerino, Italy
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11
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Schnell SA, You S, El Halawani ME. D1 and D2 dopamine receptor messenger ribonucleic acid in brain and pituitary during the reproductive cycle of the turkey hen. Biol Reprod 1999; 60:1378-83. [PMID: 10330096 DOI: 10.1095/biolreprod60.6.1378] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The regulation of prolactin secretion during the reproductive cycle of seasonal breeding birds appears to be largely under the stimulatory influence of hypothalamic vasoactive intestinal peptide (VIP). However, the factors influencing VIP secretion, and hence prolactin release, in birds remain largely unexplored. Recent evidence has demonstrated that dopamine and dopamine receptors may affect VIP and prolactin release in birds. The differential expression of dopamine receptors on hypothalamic VIP-releasing neurons may affect the degree of prolactinemia observed during the reproductive cycle of birds. In order to examine this hypothesis, we used reverse transcription-polymerase chain reaction to quantitate the levels of D1 and D2 dopamine receptor subtype mRNAs in the brain of the domestic turkey hen during the reproductive cycle. No significant difference in hypothalamic expression of D1 or D2 dopamine receptor subtypes during the reproductive cycle was observed. However, pronounced differences in D1D and D2 mRNAs were detected in cortex and cerebellum. Interestingly, there was a dramatic increase in pituitary D1D receptor mRNA during the reproductive stages of laying and incubation of eggs, which paralleled the hyperprolactinemic state of the turkey reproductive cycle. In addition, pituitary D2 receptor mRNA steadily increased throughout the reproductive cycle. In light of these observations, a modified hypothesis regarding the effects of dopamine on prolactin secretion is discussed.
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Affiliation(s)
- S A Schnell
- Department of Animal Science, University of Minnesota, St. Paul, Minnesota 55109, USA.
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12
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Barili P, Ricci A, Baldoni E, Mignini F, Amenta F. Pharmacological characterisation and autoradiographic localisation of a putative dopamine D3 receptor in the rat kidney. Eur J Pharmacol 1997; 338:89-95. [PMID: 9408008 DOI: 10.1016/s0014-2999(97)01303-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The pharmacological profile and the microanatomical localisation of a putative dopamine D3 receptor in the rat renal cortex were investigated using radioligand binding assay and light microscope autoradiography techniques. [3H]7-hydroxy-N,N-di-n-propyl-2-aminotetraline ([3H]7-OH-DPAT) was used as a ligand. [3H]7-OH-DPAT was bound specifically to sections of renal cortex. The binding was time-, temperature- and concentration-dependent, of high affinity and guanine nucleotide-insensitive. The dissociation constant (Kd) value was 0.57 +/- 0.02 nM and the maximum density of binding sites (Bmax) was 62.4 +/- 3.5 fmol/mg tissue. The pharmacological profile of [3H]7-OH-DPAT binding to sections of rat renal cortex suggests the labelling of a dopamine D3 receptor. Light microscope autoradiography revealed the accumulation of the radioligand primarily within cortical tubules and to a lesser extent in the glomerular tuft. In glomeruli, binding sites were found mainly in mesangium and mesangial cells. The demonstration of a putative dopamine D3 receptor in slide-mounted sections of rat renal cortex suggests that appropriate radioligand binding assay techniques combined with autoradiography, may contribute to characterise peripheral dopamine receptor subtypes.
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Affiliation(s)
- P Barili
- Dipartimento di Scienze Farmacologiche e Medicina Sperimentale, Università di Camerino, Italy
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13
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Barili P, Bronzetti E, Felici L, Ferrante F, Ricci A, Zaccheo D, Amenta F. Age-dependent changes in the expression of dopamine receptor subtypes in human peripheral blood lymphocytes. J Neuroimmunol 1996; 71:45-50. [PMID: 8982102 DOI: 10.1016/s0165-5728(96)00127-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The pharmacological profile and the density of dopamine D3 and D5 receptor subtypes expressed by human peripheral blood lymphocytes of subjects of different ages (ranging from 20 to 75 years) were assessed using radioligand binding techniques. Dopamine D3 receptor was assayed with [3H]7-hydroxy-N,N-di-n-propyl-2-aminotetraline ([3H]7-OH-DPAT) as a ligand. Dopamine D5 receptor was assayed using [3HIR]-(+)-(-chloro-2,3,4,5, tetrahydro-5-phenyl-1H-3-benzazepin-al-hemimaleate) ([3H]SCH 23390) as a ligand. The affinity and the pharmacological profile of [3H]7-OH-DPAT and [3H]SCH 23390 at dopamine D3 and D5 receptor, respectively, were similar in subjects of different ages. The density of dopamine D3 receptor binding sites was slightly decreased in subjects of 30-39 years in comparison with younger individuals. A remarkable loss of dopamine D3 receptor was then found between 40 and 49 years of age in comparison with younger subjects. A further slight decrease was noticeable between 50 and 59 years of age. The number of [3H]7-OH-DPAT binding sites was then stabilized after 60 years of age. The density of dopamine D5 receptor binding sites did not show age-dependent changes. The above findings indicate the occurrence of a decline in the density of lymphocyte dopamine D3 but not D5 receptor between adult and mature subjects. The possibility that dopamine D3 receptor assay in peripheral blood lymphocytes may represent a tool for investigating dopamine receptor function in aging and age-related neurological disorders is discussed.
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Affiliation(s)
- P Barili
- Sezione di Anatomia Umana, Università di Camerino, Italy
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