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Dos-Santos-Pereira M, da-Silva CA, Guimarães FS, Del-Bel E. Co-administration of cannabidiol and capsazepine reduces L-DOPA-induced dyskinesia in mice: Possible mechanism of action. Neurobiol Dis 2016; 94:179-95. [PMID: 27373843 DOI: 10.1016/j.nbd.2016.06.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 12/22/2022] Open
Affiliation(s)
- Maurício Dos-Santos-Pereira
- University of São Paulo (USP), School of Odontology of Ribeirão Preto, Department of Morphology, Physiology and Basic Pathology, Av. Café S/N, 14040-904 Ribeirão Preto, SP, Brazil; USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil; USP, Medical School of Ribeirão Preto, Department of Physiology, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Célia Aparecida da-Silva
- University of São Paulo (USP), School of Odontology of Ribeirão Preto, Department of Morphology, Physiology and Basic Pathology, Av. Café S/N, 14040-904 Ribeirão Preto, SP, Brazil; USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil
| | - Francisco Silveira Guimarães
- USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil; USP, Medical School of Ribeirão Preto, Department of Pharmacology, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Elaine Del-Bel
- University of São Paulo (USP), School of Odontology of Ribeirão Preto, Department of Morphology, Physiology and Basic Pathology, Av. Café S/N, 14040-904 Ribeirão Preto, SP, Brazil; USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil; USP, Medical School of Ribeirão Preto, Department of Physiology, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil; USP, Medical School of Ribeirão Preto, Department of Pharmacology, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil.
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Bortolanza M, Cavalcanti-Kiwiatkoski R, Padovan-Neto FE, da-Silva CA, Mitkovski M, Raisman-Vozari R, Del-Bel E. Glial activation is associated with l-DOPA induced dyskinesia and blocked by a nitric oxide synthase inhibitor in a rat model of Parkinson's disease. Neurobiol Dis 2014; 73:377-87. [PMID: 25447229 DOI: 10.1016/j.nbd.2014.10.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 10/22/2014] [Indexed: 12/22/2022] Open
Abstract
l-3, 4-dihydroxyphenylalanine (L-DOPA) is the most effective treatment for Parkinson's disease but can induce debilitating abnormal involuntary movements (dyskinesia). Here we show that the development of L-DOPA-induced dyskinesia in the rat is accompanied by upregulation of an inflammatory cascade involving nitric oxide. Male Wistar rats sustained unilateral injections of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. After three weeks animals started to receive daily treatment with L-DOPA (30 mg/kg plus benserazide 7.5 mg/kg, for 21 days), combined with an inhibitor of neuronal NOS (7-nitroindazole, 7-NI, 30 mg/kg/day) or vehicle (saline-PEG 50%). All animals treated with L-DOPA and vehicle developed abnormal involuntary movements, and this effect was prevented by 7-NI. L-DOPA-treated dyskinetic animals exhibited an increased striatal and pallidal expression of glial fibrillary acidic protein (GFAP) in reactive astrocytes, an increased number of CD11b-positive microglial cells with activated morphology, and the rise of cells positive for inducible nitric oxide-synthase immunoreactivity (iNOS). All these indexes of glial activation were prevented by 7-NI co-administration. These findings provide evidence that the development of L-DOPA-induced dyskinesia in the rat is associated with activation of glial cells that promote inflammatory responses. The dramatic effect of 7-NI in preventing this glial response points to an involvement of nitric oxide. Moreover, the results suggest that the NOS inhibitor prevents dyskinesia at least in part via inhibition of glial cell activation and iNOS expression. Our observations indicate nitric oxide synthase inhibitors as a therapeutic strategy for preventing neuroinflammatory and glial components of dyskinesia pathogenesis in Parkinson's disease.
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Affiliation(s)
- Mariza Bortolanza
- University of São Paulo (USP), School of Odontology of Ribeirao Preto, Department of Morphology, Physiology and Basic Pathology, Av. Café S/N, 14040-904 Ribeirão Preto, SP, Brazil; USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil
| | - Roberta Cavalcanti-Kiwiatkoski
- USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil; USP, Medical School, Department of Physiology, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Fernando E Padovan-Neto
- USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil; USP, Department of Behavioral Neurosciences, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Célia Aparecida da-Silva
- University of São Paulo (USP), School of Odontology of Ribeirao Preto, Department of Morphology, Physiology and Basic Pathology, Av. Café S/N, 14040-904 Ribeirão Preto, SP, Brazil; USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil
| | - Miso Mitkovski
- Light Microscopy Facility Max-Planck-Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Rita Raisman-Vozari
- Sorbonne Université UPMC UM75 INSERM U1127, CNRS UMR 7225, Institut de Cerveau et de la Moelle Epinière, Paris, France
| | - Elaine Del-Bel
- University of São Paulo (USP), School of Odontology of Ribeirao Preto, Department of Morphology, Physiology and Basic Pathology, Av. Café S/N, 14040-904 Ribeirão Preto, SP, Brazil; USP, Center for Interdisciplinary Research on Applied Neurosciences (NAPNA), Brazil; USP, Medical School, Department of Physiology, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil; USP, Department of Behavioral Neurosciences, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil.
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Del-Bel E, Padovan-Neto FE, Szawka RE, da-Silva CA, Raisman-Vozari R, Anselmo-Franci J, Romano-Dutra AC, Guimaraes FS. Counteraction by nitric oxide synthase inhibitor of neurochemical alterations of dopaminergic system in 6-OHDA-lesioned rats under L-DOPA treatment. Neurotox Res 2013; 25:33-44. [PMID: 23807548 DOI: 10.1007/s12640-013-9406-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 12/21/2022]
Abstract
Nitric oxide synthase inhibitors reduce L-3, (Del-Bel et al., Cell Mol Neurobiol 25(2):371-392, 2005) 4-dihydroxyphenylalanine (L-DOPA)-induced abnormal motor effects subsequent to depletion of dopaminergic neurons in rodents and non-human primates. The present study used quantitative high-performance liquid chromatography to analyze, for the first time, dopamine metabolism in striatum of rats in order to elucidate the mechanism of action of the nitric oxide synthase inhibitors. Adult male Wistar rats received unilateral microinjection of saline (sham) or 6-hydroxydopamine (6-OHDA-lesioned) in the medial forebrain bundle. Past 3 weeks, rats were treated during 21 days with L-DOPA/benserazide (30 mg/kg/7.5 mg/kg, respectively, daily). On the 22nd day rats received an intraperitoneal (i.p.) injection of either vehicle or 7-nitroindazole, a preferential neuronal nitric oxide synthase inhibitor before L-DOPA. Abnormal involuntary movements and rotarod test were assessed as behavioral correlate of motor responses. Lesion intensity was evaluated through tyrosine hydroxylase immunohystochemical reaction. Dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), and an extent of dopamine striatal tissue levels/dopamine metabolism were measured in the striatum. Lesion with 6-OHDA decreased dopamine, DOPAC, and DOPAC/dopamine ratio in the lesioned striatum. L-DOPA treatment induced abnormal involuntary movements and increased DOPAC/dopamine ratio (nearly five times) in the lesioned striatum. L-DOPA-induced dyskinesia was mitigated by 7-nitroindazole, which also decreased dopamine turnover, dopamine and DOPAC levels. Our results revealed an almost two times increase in dopamine content in the non-lesioned striatum of 6-OHDA-lesioned rats. Reduction of striatal DOPAC/dopamine ratio in dyskinetic rats may suggest an increase in the dopamine availability. Our data confirm contribution of nitrergic transmission in the pathogenesis of L-DOPA-induced dyskinesia with potential utilization of nitric oxide synthase inhibitors for treatment.
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Affiliation(s)
- Elaine Del-Bel
- Department of Morphology, Physiology and Pathology, School of Odontology, University of São Paulo, Campus Ribeirão Preto, Av. Café S/N, Ribeirão Preto, SP, 14040-904, Brazil,
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Schiaveto-de-Souza A, da-Silva CA, Defino HLA, Del Bel EA. Effect of melatonin on the functional recovery from experimental traumatic compression of the spinal cord. Braz J Med Biol Res 2013; 46:348-58. [PMID: 23579633 PMCID: PMC3854406 DOI: 10.1590/1414-431x20132322] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 01/21/2013] [Indexed: 01/27/2024] Open
Abstract
Spinal cord injury is an extremely severe condition with no available effective therapies. We examined the effect of melatonin on traumatic compression of the spinal cord. Sixty male adult Wistar rats were divided into three groups: sham-operated animals and animals with 35 and 50% spinal cord compression with a polycarbonate rod spacer. Each group was divided into two subgroups, each receiving an injection of vehicle or melatonin (2.5 mg/kg, intraperitoneal) 5 min prior to and 1, 2, 3, and 4 h after injury. Functional recovery was monitored weekly by the open-field test, the Basso, Beattie and Bresnahan locomotor scale and the inclined plane test. Histological changes of the spinal cord were examined 35 days after injury. Motor scores were progressively lower as spacer size increased according to the motor scale and inclined plane test evaluation at all times of assessment. The results of the two tests were correlated. The open-field test presented similar results with a less pronounced difference between the 35 and 50% compression groups. The injured groups presented functional recovery that was more evident in the first and second weeks. Animals receiving melatonin treatment presented more pronounced functional recovery than vehicle-treated animals as measured by the motor scale or inclined plane. NADPH-d histochemistry revealed integrity of the spinal cord thoracic segment in sham-operated animals and confirmed the severity of the lesion after spinal cord narrowing. The results obtained after experimental compression of the spinal cord support the hypothesis that melatonin may be considered for use in clinical practice because of its protective effect on the secondary wave of neuronal death following the primary wave after spinal cord injury.
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Affiliation(s)
- A Schiaveto-de-Souza
- Departamento de Morfofisiologia, Universidade Federal do Mato Grosso do Sul, Campo Grande, MS, Brasil
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Mitkovski M, Padovan-Neto FE, Raisman-Vozari R, Ginestet L, da-Silva CA, Del-Bel EA. Investigations into Potential Extrasynaptic Communication between the Dopaminergic and Nitrergic Systems. Front Physiol 2012; 3:372. [PMID: 23055978 PMCID: PMC3457048 DOI: 10.3389/fphys.2012.00372] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [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: 04/20/2012] [Accepted: 08/29/2012] [Indexed: 12/21/2022] Open
Abstract
Nitric oxide is unconstrained by cell membranes and can therefore act along a broad distance as a volume transmitter. Spillover of nitric oxide between neurons may have a major impact on central nervous system diseases and particularly on neurodegeneration. There is evidence whereby communication between nitrergic and dopaminergic systems plays an essential role in the control of the nigrostriatal pathway. However, there is sparse information for either the coexistence or overlap of nitric oxide and dopaminergic structures. The dual localization of immunoreactivity for nitric oxide synthase (NOS) and tyrosine hydroxylase, enzymes responsible for the synthesis of nitric oxide and dopamine, respectively, was examined in neurons of the nigrostriatal pathway in the rat brain by means of a double-immunohistochemical method and confocal laser scanning microscopy, acquired at the resolution limit. After perfusional fixation, the brains were cut and double-immunostained. A proximity analysis of tyrosine hydroxylase and NOS structures was done using binary masks generated from the respective maximum projections, using confocal laser microscopy. Unrevealed regions were determined somatodendritic positive for both NOS and tyrosine hydroxylase, within an image limit resolution at 2 μm-wide margin. The described interconnected localization of nNOS(+) and TH(+) containing neuronal fibers and cells bodies in the nigrostriatal pathway propose a close anatomical link between the two neurotransmitters.
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Affiliation(s)
- M Mitkovski
- Light Microscopy Facility, Max-Planck-Institute of Experimental Medicine Göttingen, Germany
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Echeverry MB, Salgado ML, Ferreira FR, da-Silva CA, Del Bel EA. Intracerebroventricular administration of nitric oxide-sensitive guanylyl cyclase inhibitors induces catalepsy in mice. Psychopharmacology (Berl) 2007; 194:271-8. [PMID: 17593355 DOI: 10.1007/s00213-007-0834-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Accepted: 05/21/2007] [Indexed: 12/21/2022]
Abstract
RATIONALE Catalepsy is a preclinical test that predicts extrapyramidal symptoms in humans. It models symptoms of acute extrapyramidal side effects induced at the beginning of antipsychotic treatment. Nitric oxide (NO) plays a role in a series of neurobiological functions underlying behavior. For example, inhibition of NO synthesis disrupts rodent exploratory behavior and induces catalepsy. Although several effects mediated by NO involve the activation of soluble guanylyl cyclase (sGC), the transduction mechanism of the catalepsy-inducing effect of NO has not yet been investigated. OBJECTIVES The study was designed to test if intracerebroventricular (i.c.v.) microinjection of NO-sensitive inhibitors of sGC (NO-sGC) induces catalepsy in mice similar to that induced by NO synthase (NOS) inhibitors. Exploratory behavior was tested in the open field. In addition, the effects of a NOS inhibitor on oxidative metabolites of NO were measured in the striatum. MATERIALS AND METHODS Drug effects were examined in the hanging-bar test after the following i.c.v. treatments: oxadiazolo-quinoxalin (ODQ, 30-300 nmol) or methylene blue (MB, 3-100 nmol), selective and nonselective sGC inhibitors, respectively, or 7-nitroindazole (7-NI, 3-90 nmol) and G-nitro-L: -arginine methyl ester (L: -NAME, 3-90 nmol), selective and nonselective neuronal NOS inhibitors. To test if the effects were related to interference with the NO system, additional groups received 7-NI (30 nmol), ODQ (100 nmol), or L-NAME (90 nmol) preceded by L: -arginine (L: -arg, 30-100 nmol, i.c.v. 30 min before). A possible interference of ODQ and 7-NI on exploratory behavior was tested in an open field. The concentration of nitrites and nitrates (NO( x )) in striatum homogenates was measured by the Griess reaction. RESULTS Both NO-sGC and NOS inhibitors induced catalepsy in mice that lasted for at least 2 h. The range of effective doses of these drugs, however, was limited, and the dose-effect curves had an inverted U shape. The cataleptic effect induced by L: -NAME was inversely correlated with NO( x ) products in the striatum. The cataleptic effect of 7-NI and ODQ was prevented by pretreatment with L: -arginine. No drug changed exploratory behavior in the open field. CONCLUSION This study showed that pharmacological disruption of the endogenous NO-sGC signaling in the central nervous system induces long-lasting catalepsy in mice. Moreover, the cataleptic effect of NOS inhibition correlates with the decrease in NO( x ) products formation in the striatum. The results give further support to the hypothesis that NO plays a role in motor behavior control mediated, at least in part, by cyclic guanosine monophosphate production in the striatum.
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Affiliation(s)
- M B Echeverry
- Department MEF-Physiology, FORP, University of Sao Paulo, Av. Café S/No., 14040-904, Ribeirão Preto, SP, Brazil
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Giglio CA, Defino HLA, da-Silva CA, de-Souza AS, Del Bel EA. Behavioral and physiological methods for early quantitative assessment of spinal cord injury and prognosis in rats. Braz J Med Biol Res 2007; 39:1613-23. [PMID: 17160271 DOI: 10.1590/s0100-879x2006001200013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2005] [Accepted: 09/26/2006] [Indexed: 11/22/2022] Open
Abstract
Methods for reliable evaluation of spinal cord (SC) injury in rats at short periods (2 and 24 h) after lesion were tested to characterize the mechanisms implicated in primary SC damage. We measured the physiological changes occurring after several procedures for producing SC injury, with particular emphasis on sensorimotor functions. Segmental and suprasegmental reflexes were tested in 39 male Wistar rats weighing 250-300 g divided into three control groups that were subjected to a) anesthesia, b) dissection of soft prevertebral tissue, and c) laminectomy of the vertebral segments between T10 and L1. In the lesion group the SC was completely transected, hemisected or subjected to vertebral compression. All animals were evaluated 2 and 24 h after the experimental procedure by the hind limb motility index, Bohlman motor score, open-field, hot-plate, tail flick, and paw compression tests. The locomotion scale proved to be less sensitive than the sensorimotor tests. A reduction in exploratory movements was detected in the animals 24 h after the procedures. The hot-plate was the most sensitive test for detecting sensorimotor deficiencies following light, moderate or severe SC injury. The most sensitive and simplest test of reflex function was the hot-plate. The hemisection model promoted reproducible moderate SC injury which allowed us to quantify the resulting behavior and analyze the evolution of the lesion and its consequences during the first 24 h after injury. We conclude that hemisection permitted the quantitation of behavioral responses for evaluation of the development of deficits after lesions. Hind limb evaluation scores and spontaneous exploration events provided a sensitive index of immediate injury effects after SC lesion at 2 and 24 h. Taken together, locomotion scales, open-field, and hot-plate tests represent reproducible, quantitatively sensitive methods for detecting functional deficiencies within short periods of time, indicating their potential for the study of cellular mechanisms of primary injury and repair after traumatic SC injury.
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Affiliation(s)
- C A Giglio
- Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
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Del Bel EA, Souza AS, Guimarães FS, da-Silva CA, Nucci-da-Silva LP. Motor effects of acute and chronic inhibition of nitric oxide synthesis in mice. Psychopharmacology (Berl) 2002; 161:32-7. [PMID: 11967628 DOI: 10.1007/s00213-002-1009-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2001] [Accepted: 12/28/2001] [Indexed: 10/27/2022]
Abstract
RATIONALE Systemic injections of nitric oxide synthase (NOS) inhibitors have been shown to decrease exploratory behavior in rats. This effect may be related to motor impairments since these drugs can induce catalepsy in rodents. OBJECTIVE To compare the effects of two NOS inhibitors in tests aimed to investigate exploratory behavior and to assess motor control. METHODS The acute effects of the NOS inhibitors NG-nitro- L-arginine ( L-NOARG, 10-80 mg/kg IP) and 7-nitroindazole (7-NIO, 3-30 mg/kg IP) on exploratory activity were analyzed in an open field arena. Drug effects on catalepsy were examined in the hanging-bar and wire-ring test. Footprint pattern after treatment with the two NOS inhibitors was evaluated and the results compared with those obtained with the dopamine D2 receptor antagonist haloperidol (1-2 mg/kg IP). Sub-chronic (twice a day for 4 days) effects of L-NOARG (40 mg/kg) or 7-NIO (30 mg/kg) were also tested in the open field arena and catalepsy test. RESULTS L-NOARG and 7-NIO decreased locomotion and rearing in the open field arena. Both drugs induced catalepsy in the hanging-bar test but did not change footprint pattern. The cataleptic effect of L-NOARG in the hanging bar and wire-ring tests were highly correlated ( r=0.927). The exploratory and cataleptic effects of L-NOARG and 7-NIO provided evidence for tolerance after sub-chronic treatment. CONCLUSION These results confirm that inhibition of neuronal NO formation induces impairment of exploratory behavior. This effect does not seem to involve aspects evaluated by footprint analysis, such as weight support, trunk stability and foot placement. They could, however, be related to drug-induced catalepsy.
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Affiliation(s)
- E A Del Bel
- Department MEF-Physiology, Dental School, Campus USP, Ave Café S/N0, 14040-904 Ribeirão Preto, SP, Brazil.
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Abstract
Erythrocytes may play a role in glucose homeostasis during the postprandial period. Erythrocytes from diabetic patients are defective in glucose transport and metabolism, functions that may affect glycogen storage. Phenobarbital, a hepatic enzyme inducer, has been used in the treatment of patients with non-insulin-dependent diabetes mellitus (NIDDM), increasing the insulin-mediated glucose disposal. We studied the effects of phenobarbital treatment in vivo on glycemia and erythrocyte glycogen content in control and alloxan-diabetic rats during the postprandial period. In control rats (blood glucose, 73 to 111 mg/dl in femoral and suprahepatic veins) the erythrocyte glycogen content was 45.4 +/- 1.1 and 39.1 +/- 0.8 micrograms/g Hb (mean +/- SEM, N = 4-6) in the femoral artery and vein, respectively, and 37.9 +/- 1.1 in the portal vein and 47.5 +/- 0.9 in the suprahepatic vein. Diabetic rats (blood glucose, 300-350 mg/dl) presented low (P < 0.05) erythrocyte glycogen content, i.e., 9.6 +/- 0.1 and 7.1 +/- 0.7 micrograms/g Hb in the femoral artery and vein, respectively, and 10.0 +/- 0.7 and 10.7 +/- 0.5 in the portal and suprahepatic veins, respectively. After 10 days of treatment, phenobarbital (0.5 mg/ml in the drinking water) did not change blood glucose or erythrocyte glycogen content in control rats. In diabetic rats, however, it lowered (P < 0.05) blood glucose in the femoral artery (from 305 +/- 18 to 204 +/- 45 mg/dl) and femoral vein (from 300 +/- 11 to 174 +/- 48 mg/dl) and suprahepatic vein (from 350 +/- 10 to 174 +/- 42 mg/ dl), but the reduction was not sufficient for complete recovery. Phenobarbital also stimulated the glycogen synthesis, leading to a partial recovery of glycogen stores in erythrocytes. In treated rats, erythrocyte glycogen content increased to 20.7 +/- 3.8 micrograms/g Hb in the femoral artery and 30.9 +/- 0.9 micrograms/g Hb in the suprahepatic vein (P < 0.05). These data indicate that phenobarbital activated some of the insulin-stimulated glucose metabolism steps which were depressed in diabetic erythrocytes, supporting the view that erythrocytes participate in glucose homeostasis.
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Affiliation(s)
- C A da-Silva
- Departamento de Fisiologia e Bioffsica, Universidade Estadual de Campinas, SP, Brasil
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