1
|
Roberts CJ, Hopp FA, Hogan QH, Dean C. Anandamide in the dorsal periaqueductal gray inhibits sensory input without a correlation to sympathoexcitation. Neurobiol Pain 2022; 12:100104. [PMID: 36531614 PMCID: PMC9755024 DOI: 10.1016/j.ynpai.2022.100104] [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] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/09/2022] [Accepted: 09/15/2022] [Indexed: 01/11/2023]
Abstract
There is growing literature supporting cannabinoids as a potential therapeutic for pain conditions. The development of chronic pain has been associated with reduced concentrations of the endogenous cannabinoid anandamide (AEA) in the midbrain dorsal periaqueductal gray (dPAG), and microinjections of synthetic cannabinoids into the dPAG are antinociceptive. Therefore, the goal of this study was to examine the role of the dPAG in cannabinoid-mediated sensory inhibition. Given that cannabinoids in the dPAG also elicit sympathoexcitation, a secondary goal was to assess coordination between sympathetic and antinociceptive responses. AEA was microinjected into the dPAG while recording single unit activity of wide dynamic range (WDR) dorsal horn neurons (DHNs) evoked by high intensity mechanical stimulation of the hindpaw, concurrently with renal sympathetic nerve activity (RSNA), in anesthetized male rats. AEA microinjected into the dPAG decreased evoked DHN activity (n = 24 units), for half of which AEA also elicited sympathoexcitation. AEA actions were mediated by cannabinoid 1 receptors as confirmed by local pretreatment with the cannabinoid receptor antagonist AM281. dPAG microinjection of the synaptic excitant DL-homocysteic acid (DLH) also decreased evoked DHN activity (n = 27 units), but in all cases this was accompanied by sympathoexcitation. Thus, sensory inhibition elicited from the dPAG is not exclusively linked with sympathoexcitation, suggesting discrete neuronal circuits. The rostrocaudal location of sites may affect evoked responses as AEA produced sensory inhibition without sympathetic effects at 86 % of caudal compared to 25 % of rostral sites, supporting anatomically distinct neurocircuits. These data indicate that spatially selective manipulation of cannabinoid signaling could provide analgesia without potentially harmful autonomic activation.
Collapse
Key Words
- AEA, N-arachidonylethanolamine, anandamide
- Antinociception
- CB1R, cannabinoid type one receptor
- CV, cardiovascular
- Cannabinoid
- DHN, dorsal horn neuron
- DLH, DL-homocysteic acid
- Dorsal horn
- FAAH, fatty acid amide hydrolase
- GPCR, G protein-coupled receptor
- IML, intermediolateral cell column
- MAP, mean arterial pressure
- NTS, nucleus tractus solitarius
- PAG, periaqueductal gray
- PPAR, peroxisome proliferator activated receptor
- RSNA, renal sympathetic nerve activity
- RVLM, rostral ventrolateral medulla
- RVMM, rostral ventromedial medulla
- Rat
- SIA, stress-induced analgesia
- SNS, sympathetic nervous system
- Sympathetic nervous system
- TRPV1, transient receptor potential vanilloid type 1
- WDR, wide dynamic range
- dPAG, dorsal periaqueductal gray
- vPAG, ventral periaqueductal gray
Collapse
Affiliation(s)
- Christopher J. Roberts
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA,Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA
| | - Francis A. Hopp
- Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA
| | - Quinn H. Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA,Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA
| | - Caron Dean
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA,Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA,Corresponding author at: Department of Anesthesiology, Research Service 151, Zablocki VA Medical Center, Milwaukee, WI 53295, USA.
| |
Collapse
|
2
|
Shen HY, Baer SB, Gesese R, Cook JM, Weltha L, Coffman SQ, Wu J, Chen JF, Gao M, Ji T. Adenosine-A 2A Receptor Signaling Plays a Crucial Role in Sudden Unexpected Death in Epilepsy. Front Pharmacol 2022; 13:910535. [PMID: 35754505 PMCID: PMC9218562 DOI: 10.3389/fphar.2022.910535] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
Adenosinergic activities are suggested to participate in SUDEP pathophysiology; this study aimed to evaluate the adenosine hypothesis of SUDEP and specifically the role of adenosine A2A receptor (A2AR) in the development of a SUDEP mouse model with relevant clinical features. Using a combined paradigm of intrahippocampal and intraperitoneal administration of kainic acid (KA), we developed a boosted-KA model of SUDEP in genetically modified adenosine kinase (ADK) knockdown (Adk+/-) mice, which has reduced ADK in the brain. Seizure activity was monitored using video-EEG methods, and in vivo recording of local field potential (LFP) was used to evaluate neuronal activity within the nucleus tractus solitarius (NTS). Our boosted-KA model of SUDEP was characterized by a delayed, postictal sudden death in epileptic mice. We demonstrated a higher incidence of SUDEP in Adk+/- mice (34.8%) vs. WTs (8.0%), and the ADK inhibitor, 5-Iodotubercidin, further increased SUDEP in Adk+/- mice (46.7%). We revealed that the NTS level of ADK was significantly increased in epileptic WTs, but not in epileptic Adk+/- mutants, while the A2AR level in NTS was increased in epileptic (WT and Adk+/-) mice vs. non-epileptic controls. The A2AR antagonist, SCH58261, significantly reduced SUDEP events in Adk+/- mice. LFP data showed that SCH58261 partially restored KA injection-induced suppression of gamma oscillation in the NTS of epileptic WT mice, whereas SCH58261 increased theta and beta oscillations in Adk+/- mutants after KA injection, albeit with no change in gamma oscillations. These LFP findings suggest that SCH58261 and KA induced changes in local neuronal activities in the NTS of epileptic mice. We revealed a crucial role for NTS A2AR in SUDEP pathophysiology suggesting A2AR as a potential therapeutic target for SUDEP risk prevention.
Collapse
Affiliation(s)
- Hai-Ying Shen
- Department of Neuroscience, Legacy Research Institute, Portland, OR, United States
| | - Sadie B Baer
- Department of Neuroscience, Legacy Research Institute, Portland, OR, United States
| | - Raey Gesese
- Department of Neuroscience, Legacy Research Institute, Portland, OR, United States
| | - John M Cook
- Department of Neuroscience, Legacy Research Institute, Portland, OR, United States
| | - Landen Weltha
- Department of Neuroscience, Legacy Research Institute, Portland, OR, United States
| | - Shayla Q Coffman
- Department of Neuroscience, Legacy Research Institute, Portland, OR, United States
| | - Jie Wu
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, United States
| | - Jiang-Fan Chen
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Ming Gao
- Department of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, United States
| | - Teng Ji
- Department of Pediatric Neurology, Randall Children's Hospital, Legacy Emanuel Medical Center, Portland, OR, United States
| |
Collapse
|
3
|
Holt MK, Llewellyn-Smith IJ, Reimann F, Gribble FM, Trapp S. Serotonergic modulation of the activity of GLP-1 producing neurons in the nucleus of the solitary tract in mouse. Mol Metab 2017; 6:909-921. [PMID: 28752054 PMCID: PMC5518719 DOI: 10.1016/j.molmet.2017.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 12/21/2022] Open
Abstract
Objective Glucagon-like peptide-1 (GLP-1) and 5-HT are potent regulators of food intake within the brain. GLP-1 is expressed by preproglucagon (PPG) neurons in the nucleus tractus solitarius (NTS). We have previously shown that PPG neurons innervate 5-HT neurons in the ventral brainstem. Here, we investigate whether PPG neurons receive serotonergic input and respond to 5-HT. Methods We employed immunohistochemistry to reveal serotonergic innervation of PPG neurons. We investigated the responsiveness of PPG neurons to 5-HT using in vitro Ca2+ imaging in brainstem slices from transgenic mice expressing the Ca2+ indicator, GCaMP3, in PPG neurons, and cell-attached patch-clamp recordings. Results Close appositions from 5-HT-immunoreactive axons occurred on many PPG neurons. Application of 20 μM 5-HT produced robust Ca2+ responses in NTS PPG dendrites but little change in somata. Dendritic Ca2+ spikes were concentration-dependent (2, 20, and 200 μM) and unaffected by blockade of glutamatergic transmission, suggesting 5-HT receptors on PPG neurons. Neither activation nor blockade of 5-HT3 receptors affected [Ca2+]i. In contrast, inhibition of 5-HT2 receptors attenuated increases in intracellular Ca2+ and 5-HT2C receptor activation produced Ca2+ spikes. Patch-clamp recordings revealed that 44% of cells decreased their firing rate under 5-HT, an effect blocked by 5-HT1A receptor antagonism. Conclusions PPG neurons respond directly to 5-HT with a 5-HT2C receptor-dependent increase in dendritic [Ca2+]i. Electrical responses to 5-HT revealed additional inhibitory effects due to somatic 5-HT1A receptors. Reciprocal innervation between 5-HT and PPG neurons suggests that the coordinated activity of these brainstem neurons may play a role in the regulation of food intake. Brainstem PPG neurons receive close appositions from 5-HT-containing axons. 5-HT activates NTS PPG dendrites directly via 5-HT2 receptors. 5-HT inhibits a subset of somata via 5-HT1A receptors. Activation of 5-HT3 receptors does not affect PPG cell [Ca2+]i. 5-HT2C receptor activation induces spatially confined Ca2+ spikes in PPG neurons.
Collapse
Key Words
- 5-HT, 5-hydroxytryptamine
- CCK-8, cholecystokinin-8
- CNS, central nervous system
- Dendritic calcium
- GCaMP
- GLP-1, glucagon-like peptide-1
- HPA, hypothalamic–pituitary–adrenal
- IRT, intermediate reticular nucleus
- NTS
- NTS, nucleus tractus solitarius
- PBN, parabrachial nucleus
- PPG, preproglucagon
- Preproglucagon
- Serotonin
- YFP, yellow fluorescent protein
Collapse
Affiliation(s)
- Marie K Holt
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK
| | - Ida J Llewellyn-Smith
- Cardiovascular Medicine, Human Physiology and Centre for Neuroscience, Flinders University, Bedford Park, SA 5042, Australia
| | - Frank Reimann
- Cambridge Institute for Medical Research, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Fiona M Gribble
- Cambridge Institute for Medical Research, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK.
| |
Collapse
|
4
|
Soedling H, Hodson DJ, Adrianssens AE, Gribble FM, Reimann F, Trapp S, Rutter GA. Limited impact on glucose homeostasis of leptin receptor deletion from insulin- or proglucagon-expressing cells. Mol Metab 2015; 4:619-30. [PMID: 26413468 PMCID: PMC4563029 DOI: 10.1016/j.molmet.2015.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/12/2015] [Indexed: 01/07/2023] Open
Abstract
AIMS/HYPOTHESIS The adipose tissue-derived hormone leptin plays an important role in the maintenance of body weight and glucose homeostasis. Leptin mediates its effects by interaction with leptin receptors (LepRb), which are highly expressed in the hypothalamus and other brain centres, and at lower levels in the periphery. Previous studies have used relatively promiscuous or inefficient Cre deleter strains, respectively, to explore the roles of LepR in pancreatic β and α cells. Here, we use two newly-developed Cre lines to explore the role of leptin signalling in insulin and proglucagon-expressing cells. METHODS Leptin receptor expression was measured in isolated mouse islets and highly-purified islet cells by RNASeq and quantitative RT-PCR. Mice lacking leptin signalling in pancreatic β, or in α and other proglucagon-expressing cells, were generated using Ins1Cre- or iGluCre-mediated recombination respectively of flox'd leptin receptor alleles. In vivo glucose homeostasis, changes in body weight, pancreatic histology and hormone secretion from isolated islets were assessed using standard techniques. RESULTS Leptin receptor mRNA levels were at or below the level of detection in wild-type adult mouse isolated islets and purified cells, and leptin signalling to Stat3 phosphorylation was undetectable. Whereas male mice further deleted for leptin receptors in β cells exhibited no abnormalities in glucose tolerance up to 16 weeks of age, females transiently displayed improved glucose tolerance at 8 weeks (11.2 ± 3.2% decrease in area under curve; p < 0.05), and improved (39.0 ± 13.0%, P < 0.05) glucose-stimulated insulin secretion in vitro. No differences were seen between genotypes in body weight, fasting glucose or β/α cell ratio. Deletion of LepR from α-cells, a minority of β cells, and a subset of proglucagon-expressing cells in the brain, exerted no effects on body weight, glucose or insulin tolerance, nor on pancreatic hormone secretion assessed in vivo and in vitro. CONCLUSIONS/INTERPRETATION The use here of a highly selective Cre recombinase indicates that leptin signalling plays a relatively minor, age- and sex-dependent role in the control of β cell function in the mouse. No in vivo role for leptin receptors on α cells, nor in other proglucagon-expressing cells, was detected in this study.
Collapse
Affiliation(s)
- Helen Soedling
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, du Cane Road, London W12 0NN, UK
| | - David J Hodson
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, du Cane Road, London W12 0NN, UK
| | | | - Fiona M Gribble
- University of Cambridge Metabolic Research Laboratories, Cambridge, UK
| | - Frank Reimann
- University of Cambridge Metabolic Research Laboratories, Cambridge, UK
| | - Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, du Cane Road, London W12 0NN, UK
| |
Collapse
|
5
|
Nassar NN, Abdel-Rahman AA. Brain stem adenosine receptors modulate centrally mediated hypotensive responses in conscious rats: A review. J Adv Res 2014; 6:331-40. [PMID: 26257930 PMCID: PMC4522583 DOI: 10.1016/j.jare.2014.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/08/2014] [Accepted: 12/09/2014] [Indexed: 02/07/2023] Open
Abstract
Adenosine is implicated in the modulation of cardiovascular responses either at the peripheral or at central level in experimental animals. However, there are no dedicated reviews on the involvement of adenosine in mediating the hypotensive response of centrally administered clonidine in general and specifically in aortically barodenervated rats (ABD). The conscious ABD rat model exhibits surgically induced baroreflex dysfunction and exaggerated hypotensive response, compared with conscious sham-operated (SO) rats. The current review focuses on, the role of adenosine receptors in blood pressure (BP) regulation and their possible crosstalk with other receptors e.g. imidazoline (I1) and alpha (α2A) adrenergic receptor (AR). The former receptor is a molecular target for clonidine, whose hypotensive effect is enhanced approx. 3-fold in conscious ABD rats. We also discussed how the balance between the brain stem adenosine A1 and A2A receptors is regulated by baroreceptors and how such balance influences the centrally mediated hypotensive responses. The use of the ABD rat model yielded insight into the downstream signaling cascades following clonidine-evoked hypotension in a surgical model of baroreflex dysfunction.
Collapse
Key Words
- 8-SPT, 8-(p-sulfophenyl)-theophylline. Non-selective adenosine receptor blocker
- A1, adenosine subtype A1 receptor
- A2A, adenosine subtype A2A receptor
- ABC, avidin biotin complex
- ABD rat, aortic barodenervated rat
- ATP, adenosine triphosphate
- BP, blood pressure
- CGS21680, 2-[4-[(2-carboxyethyl)phenyl]ethylaminophenyl]ethylamino]-5′-N-ethylcarboxamidoadenosine. Selective A2A receptor agonist
- CNS, central nervous system
- CPA, N6-cyclopentyladenosine. Selective A1 receptor agonist
- Central adenosine receptors
- Centrally mediated hypotension
- Clonidine
- Conscious rats
- DAG, diacylglycerol
- DPCPX, 8-cyclopentyl-1,3-dipropylxanthine. Selective A1 receptor antagonist
- ERK1/2, extracellular signal regulated kinase
- I.C., intracisternal
- I.V., intravenous
- I1, imidazoline subtype 1 receptor
- IP3, Inositol Triphosphate
- Imidazoline I1-receptor
- JNK, C-Jun N-terminal kinase
- L-NAME, Nω-nitro-l-arginine methyl ester hydrochloride. Non-selective nitric oxide synthase inhibitor
- MAPK-NOS signaling
- NO, nitric oxide
- NOS, nitric oxide synthase
- NTS, nucleus tractus solitarius
- PC-PLC, phosphatidyl choline-selective phospholipase C
- PC12 cells, pheochromocytoma cells
- PD98059, selective extracellular signal regulated kinase inhibitor
- PDE, phosphodiesterase
- PKA, protein kinase A
- RVLM, rostral ventrolateral medulla
- SAPK, stress activated protein kinase
- SCH58261, 5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo[4,3-[Formula: see text]]-1,2,4-triazolo[1,5-c]pyrimidine. Selective adenosine A2A antagonist
- SHR, spontaneously hypertensive rat
- SND, sympathetic neuronal discharge
- SO, sham operated = conscious normotensive rats
- WKY, Wistar Kyoto rat
- cAMP, cyclic adenosine monophosphate
- α2 AR, alpha 2 adrenergic receptor
- αMNE, alpha methyl norepinephrine
Collapse
Affiliation(s)
- Noha N Nassar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Egypt
| | - Abdel A Abdel-Rahman
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, NC, USA
| |
Collapse
|