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1.
Molecules ; 28(3)2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36771180

RESUMO

Wilson's disease causes copper accumulation in the liver and extrahepatic organs. The available therapies aim to lower copper levels by various means. However, a potent drug that can repair the damaged liver and brain tissue is needed. Silymarin has hepatoprotective, antioxidant, and cytoprotective properties. However, poor oral bioavailability reduces its efficacy. In this study, a "thin film hydration method" was used for synthesizing silymarin-encapsulated liposome nanoparticles (SLNPs) and evaluated them against copper toxicity, associated liver dysfunction and neurobehavioral abnormalities in Wistar rats. After copper toxicity induction, serological and behavioral assays were conducted to evaluate treatment approaches. Histological examination of the diseased rats revealed severe hepatocyte necrosis and neuronal vacuolation. These cellular degenerations were mild in rats treated with SLNPs and a combination of zinc and SLNPs (ZSLNPs). SLNPs also decreased liver enzymes and enhanced rats' spatial memory significantly (p = 0.006) in the diseased rats. During forced swim tests, SLNPs treated rats exhibited a 60-s reduction in the immobility period, indicating reduced depression. ZSLNPs were significantly more effective than traditional zinc therapy in decreasing the immobility period (p = 0.0008) and reducing liver enzymes, but not in improving spatial memory. Overall, SLNPs enhanced oral silymarin administration and managed copper toxicity symptoms.


Assuntos
Degeneração Hepatolenticular , Silimarina , Ratos , Animais , Ratos Wistar , Silimarina/uso terapêutico , Cobre/farmacologia , Lipossomos/farmacologia , Fígado , Degeneração Hepatolenticular/tratamento farmacológico , Zinco/farmacologia , Zinco/uso terapêutico
2.
Int J Mol Sci ; 23(6)2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35328564

RESUMO

Chronic liver disease (CLD) is a global threat to the human population, with manifestations resulting from alcohol-related liver disease (ALD) and non-alcohol fatty liver disease (NAFLD). NAFLD, if not treated, may progress to non-alcoholic steatohepatitis (NASH). Furthermore, inflammation leads to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Vitexin, a natural flavonoid, has been recently reported for inhibiting NAFLD. It is a lipogenesis inhibitor and activates lipolysis and fatty acid oxidation. In addition, owing to its antioxidant properties, it appeared as a hepatoprotective candidate. However, it exhibits low bioavailability and low efficacy due to its hydrophobic nature. A novel rat model for liver cirrhosis was developed by CCL4/Urethane co-administration. Vitexin encapsulated liposomes were synthesized by the 'thin-film hydration' method. Polyethylene glycol (PEG) was coated on liposomes to enhance stability and stealth effect. The diseased rats were then treated with vitexin and PEGylated vitexin liposomes, administered intravenously and orally. Results ascertained the liposomal encapsulation of vitexin and subsequent PEG coating to be a substantial strategy for treating liver cirrhosis through oral drug delivery.


Assuntos
Neoplasias Hepáticas , Hepatopatia Gordurosa não Alcoólica , Animais , Apigenina , Etanol , Lipossomos/uso terapêutico , Fígado/patologia , Cirrose Hepática/patologia , Neoplasias Hepáticas/patologia , Hepatopatia Gordurosa não Alcoólica/patologia , Polietilenoglicóis/uso terapêutico , Ratos , Ratos Sprague-Dawley
3.
Nanomaterials (Basel) ; 11(11)2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34835916

RESUMO

Metallic nanoparticles, such as gold nanoparticles (AuNPs), have been extensively studied as drug delivery systems for various therapeutic applications. However, drug-loaded-AuNPs have been rarely explored in vivo for their effect on bacteria residing inside tissues. Ciprofloxacin (CIP) is a second-generation fluoroquinolone with a broad-spectrum of antibiotic properties devoid of developing bacteria resistance. This research is focused on the synthesis and physical characterization of Ciprofloxacin-loaded gold nanoparticles (CIP-AuNPs) and their effect on the colonization of Enterococcus faecalis in the liver and kidneys of mice. The successfully prepared CIP-AuNPs were stable and exerted enhanced in vitro antibacterial activity against E. faecalis compared with free CIP. The optimized CIP-AuNPs were administered (500 µg/Kg) once a day via tail vein to infected mice for eight days and were found to be effective in eradicating E. faecalis from the host tissues. Moreover, unlike CIP, CIP-AuNPs were non-hemolytic. In summary, this study demonstrated that CIP-AuNPs are promising and biocompatible alternative therapeutics for E.-faecalis-induced infections resistant to conventional drugs (e.g., beta-lactams and vancomycin) and should be further investigated.

4.
Hum Immunol ; 82(3): 162-169, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33581927

RESUMO

Maintenance and progression of pregnancy is an intricate process governed by a variety of developmental cues. Recurrent pregnancy loss (RPL) is a complication experienced by expecting mothers that is defined as three or more consecutive pregnancy losses. This review focuses on the dysfunctions of the immune system as one of the key contributors towards RPL. The current data suggests that the alloimmune and autoimmune factors contribute to the loss of fetus. Such causes despite being recognized as a definitive reason for recurrent pregnancy loss, are still under extensive investigation with new parameters being discovered and scrutinized for their association with RPLs. More in-depth and high throughput studies are required for devising better diagnostic tools and management strategies for the affected female so that they can carry their pregnancy to term.


Assuntos
Aborto Habitual/imunologia , Sistema Imunitário/fisiologia , Imunidade/fisiologia , Gravidez/imunologia , Animais , Anticorpos/metabolismo , Autoantígenos/imunologia , Feminino , Humanos , Isoantígenos/imunologia
5.
PLoS One ; 12(12): e0187959, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29227996

RESUMO

Cytochrome P450 4x1 (Cyp4x1) is expressed at very high levels in the brain but the function of this protein is unknown. It has been hypothesised to regulate metabolism of fatty acids and to affect the activity of endocannabinoid signalling systems, which are known to influence appetite and energy metabolism. The objective of the present investigation was to determine the impact of Cyp4x1 on body weight and energy metabolism by developing a line of transgenic Cyp4x1-knock out mice. Mice were developed with a global knock-out of the gene; the full-length RNA was undetectable, and mice were viable and fertile. Both male and female Cyp4x1-knock out mice gained significantly more body weight on normal lab chow diet compared to control flox mice on the same genetic background. At necropsy, Cyp4x1-knock out male mice had significantly greater intra-abdominal fat deposits (P<0.01), and enlarged adipocytes. Metabolic rate and locomotor activity as inferred from VO2 measures and crossing of infrared beams in metabolic cages were not significantly affected by the mutation in either gender. The respiratory exchange ratio was significantly decreased in male knock out mice (P<0.05), suggesting a greater degree of fat oxidation, consistent with their higher adiposity. When mice were maintained on a high fat diet, VO2 was significantly decreased in both male and female Cyp4x1-knock out mice. We conclude that the Cyp4x1-knock out mouse strain demonstrates a mildly obese phenotype, consistent with the view that cytochrome P450 4x1 plays a role in regulating fat metabolism.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Animais , Feminino , Masculino , Camundongos , Camundongos Knockout , RNA Mensageiro/genética
6.
Org Lett ; 17(17): 4256-9, 2015 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-26278016

RESUMO

The preparation of fluoroalkoxy arylboronic esters by iridium-catalyzed aromatic C-H borylation is described. The fluoroalkoxy groups employed include trifluoromethoxy, difluoromethoxy, 1,1,2,2-tetrafluoroethoxy, and 2,2-difluoro-1,3-benzodioxole. The borylation reactions were carried out neat without the use of a glovebox or Schlenk line. The regioselectivities available through the iridium-catalyzed C-H borylation are complementary to those obtained by the electrophilic aromatic substitution reactions of fluoroalkoxy arenes. Fluoroalkoxy arylboronic esters can serve as versatile building blocks.

7.
Sci Pharm ; 78(2): 259-74, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21179339

RESUMO

The present study compares the extrapyramidal and neurochemical effects of clozapine and risperidone in rat caudate (corpus striatum) and nucleus accumbens (ventral striatum) dose-dependently. Animals injected with clozapine (2.5, 5.0 and 10.0 mg/kg IP) or risperidone (1.0, 2.5 and 5.0 mg/kg IP) in acute were sacrificed 1 h later to collect brain samples. Extrapyramidal side effects (EPS) in terms of locomotor activity and catalepsy were monitored in each animal after the drug or vehicle administration. Maximum cataleptic potentials were found only at high doses of clozapine (10.0 mg/kg; 60%) and risperidone (5.0 mg/kg; 100%). Neurochemical estimations were carried out by HPLC-EC. Both drugs at all doses significantly (p<0.01) increased the concentration of homovanillic acid (HVA), a metabolite of DA, in the caudate nucleus and decreased in nucleus accumbens. Levels of Dihydroxyphenylacetic acid (DOPAC) significantly (p<0.01) increased in the caudate by clozapine administration and decreased in the nucleus accumbens by the administration of both drugs in a dose-dependent manner. 5-Hydroxyindoleacetic acid (5-HIAA), the predominant metabolite of serotonin significantly decreased in the caudate and nucleus accumbens in a similar fashion. Levels of tryptophan (TRP) were remained insignificant in caudate and nucleus accumbens by the injections of two drugs. In caudate, clozapine and risperidone administrations significantly (p<0.01) decreased HVA/DA ratio and increased DOPAC/DA ratio in nucleus accumbens at all doses. The findings suggest the evidence for DA/5-HT receptor interaction as an important link in the lower incidence of EPS. The possible role of serotonin(1A) receptors in the pathophysiology of schizophrenia is also discussed.

8.
Acta Pharm ; 60(2): 129-40, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21134850

RESUMO

The present study was designed to evaluate the behavioral and neurochemical profiles of clozapine and risperidone in rats in a dose-dependent manner. Animals injected intraperitoneally (i.p.) with clozapine (2.5, 5.0 and 10.0 mg kg-1) or risperidone (1.0, 2.5 and 5.0 mg kg-1) were sacrificed 1 h later to collect brain samples. Hypolocomotive effects (home cage activity and catalepsy) were successively monitored in each animal after the drug or saline administration. Both drugs significantly (p < 0.01) decreased locomotor activity at high doses and in a dose-dependent manner. Maximum (100%) cataleptic potential was achieved at a high dose (5.0 mg kg-1) of risperidone. Neurochemical estimations were carried out by HPLC with electrochemical detection. Both drugs, at all doses, significantly (p < 0.01) increased the concentration of homovanillic acid (HVA), a metabolite of dopamine (DA), in the striatum. Dihydroxyphenylacetic acid (DOPAC) levels increased in the striatum and decreased in the rest of the brain, particularly in clozapine-injected rats. 5-Hydroxyindoleacetic acid (5-HIAA), the predominant metabolite of serotonin, significantly (p < 0.01) decreased in the striatum. 5-Hydroxytryptamine (5-HT) was significantly (p < 0.01) increased by risperidone and decreased by clozapine in the rest of the brain. Striatal tryptophan (TRP) was significantly (p < 0.01) decreased by risperidone and increased in the rest of the brain. The striatal HVA/DA ratio increased and the 5-HT turnover rate remained unchanged in the rest of the brain. Results suggest that the affinity of the two drugs towards D2/5-HT1A receptors interaction is involved in lower incidence of extrapyramidal side effects. Role of 5-HT1A receptors in the treatment of schizophrenia is discussed.


Assuntos
Clozapina/farmacologia , Dopamina/metabolismo , Tratos Extrapiramidais/efeitos dos fármacos , Risperidona/farmacologia , Serotonina/metabolismo , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Antipsicóticos/farmacocinética , Antipsicóticos/farmacologia , Comportamento/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Clozapina/farmacocinética , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Antagonistas de Dopamina/farmacocinética , Antagonistas de Dopamina/farmacologia , Relação Dose-Resposta a Droga , Tratos Extrapiramidais/metabolismo , Tratos Extrapiramidais/fisiologia , Ácido Homovanílico/metabolismo , Ácido Hidroxi-Indolacético/metabolismo , Masculino , Atividade Motora/efeitos dos fármacos , Ratos , Ratos Wistar , Receptor 5-HT1A de Serotonina/metabolismo , Receptores de Dopamina D2/metabolismo , Risperidona/farmacocinética , Antagonistas da Serotonina/farmacocinética , Antagonistas da Serotonina/farmacologia , Triptofano/metabolismo , Córtex Visual/efeitos dos fármacos , Córtex Visual/metabolismo
9.
Med Sci Monit ; 16(8): BR285-92, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20671610

RESUMO

BACKGROUND: Long-term treatment of haloperidol, a neuroleptic, induces neurodegeneration specifically in the striatum (caudate and putamen), which plays an important role in the development of orofacial dyskinesia, a putative model of tardive dyskinesia (TD). This study investigated the protective effects of a concomitant treatment of aqueous fruit extract of Sea buckthorn (Hippophae rhamnoides L. spp. Turkestanica) (SBT-FE) (40 mg/kg, orally) plus haloperidol (3.0 mg/kg, ip) administration on an animal model of TD and on striatal neuronal alterations. MATERIAL/METHODS: Rats received daily haloperidol (3.0 mg/kg ip) and saline injections for 15 days. Seven-day posttreatment, aqueous SBT-FE (40 mg/kg) was administered daily via a feeding tube. Hypolocomotive effects (home cage activity, exploratory activity, catalepsy, and vacuous chewing movements) were monitored consecutively in each group. On the last day of the experiments, changes in extracellular levels of striatal dopamine (DA), dihydroxyphenyl acetic acid (DOPAC) and homovanillic acid (HVA) were determined by HPLC-EC. RESULTS: Aqueous SBT-FE attenuated haloperidol-induced VCMs after second week of treatment and locomotor activity was greater in rats treated with SBT-FE compared with the controls. The results indicate that DA and HVA levels in the striatum were significantly (P <.01) altered in rats given SBT-FE before injections of haloperidol. CONCLUSIONS: Hippophae rhamnoides fruit extract has a protective role against haloperidol-induced orofacial dyskinesia. Consequently, use of Hippophae rhamnoides as a possible therapeutic agent for the treatment of tardive dyskinesia should be considered.


Assuntos
Haloperidol/efeitos adversos , Hippophae/química , Transtornos dos Movimentos/tratamento farmacológico , Neostriado/patologia , Neurônios/patologia , Extratos Vegetais/uso terapêutico , Substâncias Protetoras/uso terapêutico , Administração Oral , Animais , Catalepsia/complicações , Dopamina/metabolismo , Comportamento Exploratório/efeitos dos fármacos , Frutas/química , Ácido Homovanílico/metabolismo , Masculino , Atividade Motora/efeitos dos fármacos , Transtornos dos Movimentos/complicações , Neostriado/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fitoterapia , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacologia , Substâncias Protetoras/administração & dosagem , Substâncias Protetoras/farmacologia , Ratos , Ratos Wistar
10.
J Coll Physicians Surg Pak ; 19(3): 139-45, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19268010

RESUMO

OBJECTIVE: To investigate the effects of orally supplemented amino acids L-Tryptophan (Trp) and L-Valine (Val) in rats repeatedly injected with haloperidol following one week of drug withdrawal, with particular reference to extrapyramidal symptoms (EPS) and serotonin (5-hydroxytryptamine; 5-HT) metabolism in medial prefrontal cortex (mPFC). STUDY DESIGN: Experimental study. PLACE AND DURATION OF STUDY: Department of Biochemistry, University of Karachi from December 2007 to February 2008. METHODOLOGY: The study was conducted on thirty six locally bred male Albino Wistar rats. Freshly prepared amino acids (Val and Trp) were added in the drinking water of rats on alternate days and haloperidol at doses of 5.0 mg/kg or saline were injected twice daily for three weeks following one week of withdrawal. Locomotor/ exploratory activities were scored in activity boxes and open field apparatuses. Catalepsy was monitored on an inclined surface. The animals tested for locomotor activity and catalepsy for two weeks follow-up post-injections plus one week of drug withdrawal were decapitated to collect mPFC regions of rat brain for neurochemical analysis by high performance liquid chromatography with electrochemical detection (HPLC-EC). RESULTS: There was significant increase (p<0.01) in locomotor activity in rats orally supplemented with Val and Trp following one week of drug withdrawal from repeated administration. Marked reduction in cataleptogenic effects of the drug was also observed. Significant (p<0.01) increases in the brain Trp and mPFC 5-HT metabolism in Val and Trp supplemented animals were also noticed. CONCLUSION: These findings help to demonstrate the effect of dietary amino acids, in particular, Trp to potentiate mPFC serotonergic modulation of neuroleptic activity.


Assuntos
Suplementos Nutricionais , Lobo Frontal/metabolismo , Haloperidol , Serotonina/metabolismo , Síndrome de Abstinência a Substâncias/fisiopatologia , Triptofano/farmacologia , Valina/farmacologia , Animais , Catalepsia/induzido quimicamente , Haloperidol/farmacologia , Masculino , Ratos , Ratos Wistar
11.
Pak J Pharm Sci ; 21(4): 411-20, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18930864

RESUMO

The idea that serotonin (5-hydroxytryptamine; 5-HT) is contributed in schizophrenia has long been advocated and alterations in 5-HT neurotransmission has been hypothesized to modulate both the therapeutic and extrapyramidal symptoms (EPS) liability of conventional neuroleptics. The 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), a preferential 5-HT(1A) ligand, has been reported to attenuate EPS functions of haloperidol in animals. In view of a possible role of 5-HT(1A) receptors in the management of EPS functions of a neuroleptic drug, the present study was designed to investigate behavioral responses of 8-OH-DPAT at a challenge dose of 0.5mg/Kg in rats with subchronic haloperidol administration at a dose of 5mg/Kg twice daily for 5 days. The intensity of 5-HT syndrome provoked by 8-OH-DPAT was taken as a measure of postsynaptic responses. In the present study administration of haloperidol at a dose of 5mg/Kg twice daily for 5 days decreased locomotion significantly (p<0.01) in familiar (home cage) environment. Subchronic administration of haloperidol at the same dose elicited significant (p<0.01) cataleptic responses in rats when compared with saline treated rats. Results revealed that 8-OH-DPAT-induced hyperlocomotion (p<0.05) and forepaw treading (p<0.1) were significantly smaller in rats pre-treated with haloperidol for 5 days than repeatedly saline injected rats. Conversely, the other components of the syndrome i.e. flat body posture (p<0.001), hind limb abduction (p<0.001) and straub tail (p<0.01) were significantly greater in repeated haloperidol treated rats when compared with repeated saline injected rats. These findings help to demonstrate a causal link between the upregulation of DA-D(2) receptors and the decrease in the effectiveness of presynaptic 5-HT(1A) receptors following subchronic haloperidol administration and this may further help to yield an antipsychotic agent with an improved profile of efficacy to EPS, thereby widening its therapeutic window.


Assuntos
8-Hidroxi-2-(di-n-propilamino)tetralina/farmacologia , Doenças dos Gânglios da Base/tratamento farmacológico , Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Receptores Pré-Sinápticos/agonistas , Agonistas do Receptor 5-HT1 de Serotonina , Agonistas do Receptor de Serotonina/farmacologia , Animais , Doenças dos Gânglios da Base/induzido quimicamente , Doenças dos Gânglios da Base/metabolismo , Encéfalo/metabolismo , Modelos Animais de Doenças , Haloperidol , Locomoção/efeitos dos fármacos , Masculino , Ratos , Ratos Wistar , Receptor 5-HT1A de Serotonina/metabolismo , Receptores de Dopamina D2/efeitos dos fármacos , Receptores Pré-Sinápticos/metabolismo , Síndrome da Serotonina/induzido quimicamente , Síndrome da Serotonina/metabolismo , Fatores de Tempo , Regulação para Cima
12.
Pharmacol Rep ; 59(2): 173-80, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17556795

RESUMO

8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a selective 5-hydroxytryptamine 1A (serotonin; 5-HT1A) agonist was used to evaluate the role of somatodendritic and/or postsynaptic 5-HT1A receptors following exposure to restraint stress. Exposure to an episode of 2-h restraint stress decreased 24 h cumulative food intake. Intensity of 8-OH-DPAT-induced 5-HT syndrome monitored next day was smaller in restrained than unrestrained animals. Hyperphagic effects of 8-OH-DPAT were comparable in the two groups. Restrained animals injected with saline exhibited an increase in 5-HT levels in the hippocampus, hypothalamus and cortex but not in the midbrain and striatum. 5-Hydroxyindolacetic acid (5-HIAA) increased in the hippocampus, midbrain and cortex but not in the hypothalamus and striatum. 8-OH-DPAT injected at a dose of 0.25 mg/kg decreased 5-HT and 5-HIAA levels in different brain regions of unrestrained as well as restrained animals. The decreases were greater in restrained than unrestrained animals, suggesting a supersensitivity of somatodendritic 5-HT1A receptors. The results are discussed in the context of a role of 5-HT1A receptor in restraint-induced behavioral deficits.


Assuntos
8-Hidroxi-2-(di-n-propilamino)tetralina/farmacologia , Receptor 5-HT1A de Serotonina/fisiologia , Agonistas do Receptor de Serotonina/farmacologia , Estresse Psicológico/metabolismo , Estresse Psicológico/psicologia , Animais , Química Encefálica/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Ácido Hidroxi-Indolacético/análise , Masculino , Ratos , Ratos Wistar , Restrição Física , Serotonina/análise
13.
Med Sci Monit ; 8(9): BR354-61, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12218936

RESUMO

BACKGROUND: An important goal of current neuroleptic research is to develop antipsychotic compounds with a low incidence of extrapyramidal side effects (EPS). Clozapine, the first of the atypical antipsychotics to be proven effective in treatment-resistant schizophrenia, is reported to produce less EPS than typical neuroleptics, such as haloperidol. MATERIAL/METHODS: The present study compares the neurochemical profiles of clozapine and haloperidol in rats. Animals injected (i.p.) with haloperidol or clozapine were sacrificed 1h later to collect brain samples. Neurochemical estimations were carried out by HPLC-EC. RESULTS: Administration of haloperidol at doses of 1.0, 2.5 and 5.0 mg/kg increased the concentration of homovanillic acid (HVA), a metabolite of dopamine (DA), in the striatum and rest of the brain. Clozapine-injected rats (2.5, 5.0 and 10.0 mg/kg) showed smaller increases in the striatum, but not in the rest of the brain. Dihydroxyphenylacetic acid (DOPAC), another DA metabolite not affected by haloperidol, increased in the striatum and decreased in the rest of the brain of clozapine-injected rats. 5-Hydroxyindoleacetic acid, the predominant metabolite of serotonin, increased with haloperidol and decreased with clozapine. A high dose of haloperidol (5.0 mg/kg) increased DA and 5-HT, while an equivalent does of clozapine (10.0 mg/kg) decreased levels in the rest of the brain. The effects of both drugs on the HVA/5-HIAA and DOPAC/5-HIAA ratios were also different. CONCLUSIONS: The differing activities of the two drugs at DA and serotonin receptors implies an important role for serotonin in treatment-resistant schizophrenia and a lower incidence of EPS.


Assuntos
Encéfalo/efeitos dos fármacos , Clozapina/farmacologia , Dopamina/metabolismo , Haloperidol/farmacologia , Serotonina/metabolismo , Animais , Encéfalo/metabolismo , Cromatografia Líquida de Alta Pressão , Clozapina/efeitos adversos , Antagonistas de Dopamina/efeitos adversos , Antagonistas de Dopamina/farmacologia , Relação Dose-Resposta a Droga , Haloperidol/efeitos adversos , Masculino , Ratos , Ratos Wistar , Antagonistas da Serotonina/efeitos adversos , Antagonistas da Serotonina/farmacologia , Fatores de Tempo
14.
Artigo em Inglês | MEDLINE | ID: mdl-11853106

RESUMO

In view of a role of pre- and postsynaptic serotonin (5-hydroxytryptamine; 5-HT) receptors in adaptation to stress, effects of 1-(1-naphthylpiperazine) (1-NP) were compared in unrestrained and repeatedly restrained adapted rats. In the first part of the study, effects of various doses (1.0-15 mg/kg ip) of 1-NP were monitored on brain 5-HT metabolism (presynaptic response) and on the activity (postsynaptic response) of rats in an activity cage to which the rats were habituated before the drug administration. The drug injected at doses of 2.5-15.0 mg/kg increased motor activity and decreased brain 5-hydroxyindoleacetic acid (5-HIAA) concentration in a dose-dependent manner. In the second part of the study, rats were restrained on wire grids 2 h/day for 5 days. First-day episode of 2-h restraint decreased 24-h cumulative food intake, water intake and growth rate. The decreases attenuated following second-, third- and fourth-day episodes of 2-h restraint were not observed following fifth-day episode of 2-h restraint stress, suggesting adaptation to the stress schedule has occurred. Serotonergic and motor responses to 1-NP in unrestrained and repeatedly restrained adapted rats were compared by injecting the drug at a dose of 5 mg/kg, a dose that above results suggested would not produce maximal effects on 5-HT metabolism or motor activity. Administration of 1-NP at a dose of 5 mg/kg increased motor activity and decreased brain 5-HIAA concentration in unrestrained and repeatedly restrained adapted rats. Increases of motor activity were much greater in repeatedly restrained adapted than unrestrained rats. Decreases of 5-HIAA concentration were comparable in the two groups. The results are discussed in the context of an increase in the effectiveness of postsynaptic 5-HT-1A and 5-HT-1B receptors and a decrease in the effectiveness of presynaptic 5-HT-1A (somatodendritic) and 5-HT-1B (terminal) receptors following adaptation to stress. It is suggested that these changes of receptor responsiveness might help coping with stress demand to produce adaptation to stress.


Assuntos
Potenciais Pós-Sinápticos Excitadores/fisiologia , Atividade Motora/efeitos dos fármacos , Piperazinas/farmacologia , Serotonina/metabolismo , Estresse Psicológico/fisiopatologia , Transmissão Sináptica/fisiologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Modelos Animais de Doenças , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Ácido Hidroxi-Indolacético/metabolismo , Masculino , Ratos , Ratos Wistar , Restrição Física , Transmissão Sináptica/efeitos dos fármacos , Triptofano/metabolismo
15.
Pak J Pharm Sci ; 15(1): 71-82, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16414870

RESUMO

In view of a possible role of presynaptic serotonin (5-hydroxytryptamine, 5-HT) receptors in the precipitation of extrapyramidal side effects (EPS), the present study was designed to investigate the neurochemical effects of a selective 5-HT1A ligand, 8-hydroxy-2- (di-n-propylamino) tetralin (8-OH-DPAT) in rats following single (5 mg/kg) and repeated (two-times a day for 9 days at dosage of 5mg/kg) haloperidol administration. Haloperidol plus 8-OH-DPAT injected animals exhibited a decrease in dopamine (DA) and an increase in DA metabolite homovanillic acid (HVA) levels in the striatum and rest of the brain. The two groups of animals exhibited comparable levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the striatum and rest of the brain. Animals injected with haloperidol and killed 24 hrs after the last injection of haloperidol exhibited higher DA and HVA levels in the striatum but not in the rest of the brain. Conversely, dihydroxyphenylacetic acid (DOPAC), the other metabolite of DA, decreased in the rest of the brain. 5-HIAA concentrations increased in the striatum but not in the rest of the brain. Administration of 8-OH-DPAT significantly decreased 5-HT and 5-HIAA levels in the rest of brain and did not alter 5-HIAA in the striatum of repeated saline injected rats. Conversely, same dose of 8-OH-DPAT injected to repeatedly haloperidol injected animals did not decrease 5-HT and 5-HIAA concentrations in the rest of the brain but decreased 5-HIAA levels in the striatum. No effect of 8-OH-DPAT injections occurred on striatal or rest of the brain DA metabolism in repeatedly saline injected animals except that DOPAC decreased in the striatum of both groups. The results are discussed in the context of a role of somatodendritic 5-HT1A receptors in the regulation of DA metabolism following single and repeated administration of haloperidol. It is suggested that an increase in the responsiveness of these receptors may be involved in the precipitation of EPS observed in patients on haloperidol therapy.

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