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Flores RA, Dos-Santos RC, Steinbach R, Rodrigues-Santos I, de Jesus AA, Antunes-Rodrigues J, Paschoalini MA. α-1 Adrenoceptor Activation in the Dorsal Raphe Nucleus Decreases Food Intake in Fasted Rats. Front Physiol 2021; 12:775070. [PMID: 34899395 PMCID: PMC8656260 DOI: 10.3389/fphys.2021.775070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/21/2021] [Indexed: 01/12/2023] Open
Abstract
The dorsal raphe (DR) nucleus is involved in a myriad of physiological functions, such as the control of sleep-wake cycle, motivation, pain, energy balance, and food intake. We have previously demonstrated that in ad libitum fed rats the intra-DR administration of phenylephrine, an α-1 receptor agonist, does not affect food intake, whereas clonidine, an α-2 receptor agonist, potently stimulates food intake. These results indicated that in fed rats an increased adrenergic tonus blocked food intake, since the activation of α-2 auto-receptors, which decreases pre-synaptic release of adrenaline/noradrenaline, affected food intake. Thus, in this study we assessed whether the response to adrenergic stimuli would differ after overnight fasting, a situation of low adrenergic activity in the DR. Intra-DR administration of adrenaline and noradrenaline blocked food intake evoked by overnight fasting. Similarly, phenylephrine administration decreased hunger-induced food intake. These changes in food intake were accompanied by changes in other behaviors, such as increased immobility time and feeding duration. On the other hand, intra-DR administration of clonidine did not affect food-intake or associated behaviors. These results further support the hypothesis that in fed animals, increased adrenergic tonus in DR neurons inhibiting feeding, while in fasted rats the adrenergic tonus decreases and favors food intake. These data indicate a possible mechanism through which adrenergic input to the DRN contributes to neurobiology of feeding.
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Affiliation(s)
- Rafael Appel Flores
- Department of Physiology, Ribeirão Preto School of Medicine, São Paulo University, Ribeirão Preto, Brazil.,Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Raoni Conceição Dos-Santos
- Department of Physiology, Ribeirão Preto School of Medicine, São Paulo University, Ribeirão Preto, Brazil
| | - Renata Steinbach
- Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Isabelle Rodrigues-Santos
- Department of Physiology, Ribeirão Preto School of Medicine, São Paulo University, Ribeirão Preto, Brazil
| | - Aline Alves de Jesus
- Department of Physiology, Ribeirão Preto School of Medicine, São Paulo University, Ribeirão Preto, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, Ribeirão Preto School of Medicine, São Paulo University, Ribeirão Preto, Brazil
| | - Marta Aparecida Paschoalini
- Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
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Evaluation of food intake and Fos expression in serotonergic neurons of raphe nuclei after intracerebroventricular injection of adrenaline in free-feeding rats. Brain Res 2018; 1678:153-163. [DOI: 10.1016/j.brainres.2017.10.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/21/2017] [Accepted: 10/22/2017] [Indexed: 02/05/2023]
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Silva ESD, Flores RA, Ribas AS, Taschetto AP, Faria MS, Lima LB, Metzger M, Donato J, Paschoalini MA. Injections of the of the α 1 -adrenoceptor antagonist prazosin into the median raphe nucleus increase food intake and Fos expression in orexin neurons of free-feeding rats. Behav Brain Res 2017; 324:87-95. [DOI: 10.1016/j.bbr.2017.02.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/02/2017] [Accepted: 02/11/2017] [Indexed: 02/02/2023]
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Zendehdel M, Sardari F, Hassanpour S, Rahnema M, Adeli A, Ghashghayi E. Serotonin-induced hypophagia is mediated via α2 and β2 adrenergic receptors in neonatal layer-type chickens. Br Poult Sci 2017; 58:298-304. [DOI: 10.1080/00071668.2017.1278626] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- M. Zendehdel
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - F. Sardari
- Department of Physiology, Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran
| | - S. Hassanpour
- Department of Basic Sciences, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - M. Rahnema
- Department of Physiology, Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran
| | - A. Adeli
- Department of Basic Sciences, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - E. Ghashghayi
- Department of Physiology, Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran
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Brierley DI, Samuels J, Duncan M, Whalley BJ, Williams CM. Cannabigerol is a novel, well-tolerated appetite stimulant in pre-satiated rats. Psychopharmacology (Berl) 2016; 233:3603-13. [PMID: 27503475 PMCID: PMC5021742 DOI: 10.1007/s00213-016-4397-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 07/19/2016] [Indexed: 11/26/2022]
Abstract
RATIONALE The appetite-stimulating properties of cannabis are well documented and have been predominantly attributed to the hyperphagic activity of the psychoactive phytocannabinoid, ∆(9)-tetrahydrocannabinol (∆(9)-THC). However, we have previously shown that a cannabis extract devoid of ∆(9)-THC still stimulates appetite, indicating that other phytocannabinoids also elicit hyperphagia. One possible candidate is the non-psychoactive phytocannabinoid cannabigerol (CBG), which has affinity for several molecular targets with known involvement in the regulation of feeding behaviour. OBJECTIVES The objective of the study was to assess the effects of CBG on food intake and feeding pattern microstructure. METHODS Male Lister hooded rats were administered CBG (30-120 mg/kg, per ora (p.o.)) or placebo and assessed in open field, static beam and grip strength tests to determine a neuromotor tolerability profile for this cannabinoid. Subsequently, CBG (at 30-240 mg/kg, p.o.) or placebo was administered to a further group of pre-satiated rats, and hourly intake and meal pattern data were recorded over 2 h. RESULTS CBG produced no adverse effects on any parameter in the neuromotor tolerability test battery. In the feeding assay, 120-240 mg/kg CBG more than doubled total food intake and increased the number of meals consumed, and at 240 mg/kg reduced latency to feed. However, the sizes or durations of individual meals were not significantly increased. CONCLUSIONS Here, we demonstrate for the first time that CBG elicits hyperphagia, by reducing latency to feed and increasing meal frequency, without producing negative neuromotor side effects. Investigation of the therapeutic potential of CBG for conditions such as cachexia and other disorders of eating and body weight regulation is thus warranted.
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Affiliation(s)
- Daniel I Brierley
- School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
- School of Chemistry, Food and Pharmacy, University of Reading, Reading, UK
| | - James Samuels
- School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
| | | | - Benjamin J Whalley
- School of Chemistry, Food and Pharmacy, University of Reading, Reading, UK
| | - Claire M Williams
- School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK.
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Levone BR, Cella EC, Kochenborger L, da Silva ES, Taschetto APD, Mansur SS, Terenzi MG, Faria MS, Paschoalini MA. Ingestive and locomotor behaviours induced by pharmacological manipulation of <Alpha>-adrenoceptors into the median raphe nucleus. Neuropharmacology 2014; 89:136-45. [PMID: 25261784 DOI: 10.1016/j.neuropharm.2014.09.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 08/28/2014] [Accepted: 09/15/2014] [Indexed: 12/21/2022]
Abstract
The present study evaluated the involvement of α-adrenoceptors of the median raphe nucleus (MRN) in satiated rats, in food and water intake and motor behaviour. Control groups were treated with saline (SAL) or adrenaline (ADR), injected into the MRN seven minutes after injection of the vehicle used to solubilize the antagonists, propylene glycol (PLG) or SAL. Experimental groups were treated with an α-adrenoceptor antagonist, prazosin (α1, 20 or 40 nmol) or yohimbine (α2, 20 or 40 nmol) or phentolamine (non-selective α, 20 or 40 nmol), followed (later) by injection of ADR or SAL. Behaviour was recorded for 30 min. The injection of ADR and the blockade of α1 receptors resulted in hyperphagia whereas blocking α2 or α1 and α2 simultaneously did not change feeding behaviour. Pre-treatment with prazosin, followed by injection of ADR was not able to cause an increase in the amount of food ingested, while the higher dose of the α1 antagonist reduced the latency to start feeding. Pre-treatment with prazosin also caused hyperactivity. However, pre-treatment with phentolamine or yohimbine was able to block ADR-induced feeding. The present study supports the hypothesis that there is a tonic activation of α1-adrenoceptors in the MRN in satiated rats, which activates an inhibitory influence in areas that control food intake. Injection of ADR seems to activate α2 receptors, resulting in a decrease in the availability of endogenous catecholamines, which reduces the release of the signal that inhibits food intake, leading to hyperphagia.
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Affiliation(s)
- Brunno Rocha Levone
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
| | - Elisa Caroline Cella
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
| | - Larissa Kochenborger
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
| | - Eduardo Simão da Silva
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
| | - Ana Paula Dambros Taschetto
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
| | - Samira Schultz Mansur
- Department of Morphological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), Florianopolis, SC, Brazil.
| | - Mariana Graciela Terenzi
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
| | - Moacir Serralvo Faria
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
| | - Marta Aparecida Paschoalini
- Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil.
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da Silva ES, Flores RA, Cella EC, Levone BR, Taschetto AP, Kochenborger L, Terenzi MG, Faria MS, Paschoalini MA. Blockade of median raphe nucleus α1-adrenoceptor subtypes increases food intake in rats. Pharmacol Biochem Behav 2014; 124:350-5. [DOI: 10.1016/j.pbb.2014.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 06/11/2014] [Accepted: 06/15/2014] [Indexed: 10/25/2022]
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