6 results on '"Javad Mirnajafi-Zadeh"'
Search Results
2. The blockade of GABAA receptors attenuates the inhibitory effect of orexin type 1 receptors antagonist on morphine withdrawal syndrome in rats
- Author
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Mahnaz Davoudi, Hossein Azizi, Saeed Semnanian, and Javad Mirnajafi-Zadeh
- Subjects
Male ,0301 basic medicine ,Agonist ,medicine.medical_specialty ,Microinjections ,medicine.drug_class ,Neuroscience(all) ,Narcotic Antagonists ,(+)-Naloxone ,Pharmacology ,Bicuculline ,03 medical and health sciences ,0302 clinical medicine ,Orexin Receptors ,Internal medicine ,medicine ,Animals ,Urea ,GABA-A Receptor Antagonists ,Naphthyridines ,Rats, Wistar ,Benzoxazoles ,Morphine ,Naloxone ,Chemistry ,Kindling ,GABAA receptor ,General Neuroscience ,Orexin receptor ,Substance Withdrawal Syndrome ,Orexin ,030104 developmental biology ,Endocrinology ,Locus Coeruleus ,Orexin Receptor Antagonists ,030217 neurology & neurosurgery ,medicine.drug - Abstract
The aim of present study was to investigate the involvement of orexin-A neuropeptide in naloxone-induced morphine withdrawal syndrome via modulating neurons bearing GABAA receptors. The locus coeruleus (LC) is a sensitive site for expression of the somatic aspects of morphine withdrawal. Intra-LC microinjection of GABAA receptor agonist attenuates morphine withdrawal signs in rats. Here we studied the influence of LC orexin type 1 receptors blockade by SB-334867 in presence of bicuculline, a GABAA receptor antagonist, on naloxone-induced morphine withdrawal syndrome. Adult male Wistar rats, weighing 250-300 g, were rendered dependent on morphine by subcutaneous (s.c.) injection of increasing morphine doses (6, 16, 26, 36, 46, 56 and 66 mg/kg, 2 ml/kg) at set intervals of 24 h for 7 days. On 8th day, naloxone (3 mg/kg, s.c.) was injected and the somatic signs of morphine withdrawal were evaluated. Intra-LC microinjections (0.2 μl) of either bicuculline (15 μM) or SB-334867 (3 mM) or a combination of both chemicals were done immediately before naloxone injection. Intra-LC microinjection of bicuculline (15 μM) had no significant effect on morphine withdrawal signs, whereas intra-LC microinjection of SB-334867 considerably attenuated morphine withdrawal signs. However, the effect of SB-334867 in attenuating naloxone-induced morphine withdrawal signs was blocked in presence of bicuculline. This finding, for the first time, indicated that orexin-A may participate in expression of naloxone-induced morphine withdrawal syndrome partly through decreasing the activity of neurons bearing GABAA receptors.
- Published
- 2016
3. Orexin A presynaptically decreases inhibitory synaptic transmission in rat locus coeruleus neurons
- Author
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Saeed Semnanian, Ali R. Mani, Javad Mirnajafi-Zadeh, Hossein Azizi, and Hossein Mohammad-Pour Kargar
- Subjects
0301 basic medicine ,AM251 ,Male ,Lateral hypothalamus ,Presynaptic Terminals ,Neurotransmission ,Inhibitory postsynaptic potential ,Synaptic Transmission ,03 medical and health sciences ,Orexin-A ,0302 clinical medicine ,SB-334867 ,Receptor, Cannabinoid, CB1 ,mental disorders ,medicine ,Animals ,Urea ,Naphthyridines ,Rats, Wistar ,Neurons ,Benzoxazoles ,Orexins ,Dose-Response Relationship, Drug ,Chemistry ,General Neuroscience ,digestive, oral, and skin physiology ,Neural Inhibition ,Orexin ,Rats ,030104 developmental biology ,nervous system ,Inhibitory Postsynaptic Potentials ,Locus coeruleus ,Locus Coeruleus ,Neuroscience ,hormones, hormone substitutes, and hormone antagonists ,psychological phenomena and processes ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Locus coeruleus nucleus (LC) is a major noradrenergic nucleus in the brain. It receives dense orexinergic projections from lateral hypothalamus. Whilst it is known that orexin A increases firing rate of LC neurons, its effect on spontaneous and evoked inhibitory postsynaptic currents (sIPSCs and eIPSCs, respectively) has not been yet identified. In this research, we investigated the effect of orexin A on eIPSCs and sIPSCs in LC neurons. Whole-cell recordings revealed that orexin A suppresses eIPSCs amplitude in which this effect was blocked by an orexin type-1 receptors antagonist (SB-334867) and cannabinoid type-1 (CB1) receptors antagonist (AM251). Moreover, exposure of neurons to BAPTA (Ca2+ chelator) and U73122 (phospholipase C inhibitor) prevented orexin A-induced eIPSCs depression. On the other hand, orexin A increased pair pulse ratio and sIPSCs frequency but had no effect on sIPSCs amplitude. Our results revealed that eIPSCs suppression in the LC is mediated by CB1 receptor through a presynaptic mechanism.
- Published
- 2018
4. Blockade of orexin type-1 receptors in locus coeruleus nucleus attenuates the development of morphine dependency in rats
- Author
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Mohammad Javan, Saeed Semnanian, Javad Mirnajafi-Zadeh, Hossein Azizi, and Yousof Mousavi
- Subjects
Male ,medicine.medical_specialty ,medicine.drug_class ,Physical dependence ,(+)-Naloxone ,Pharmacology ,SB-334867 ,Orexin Receptors ,Internal medicine ,medicine ,Animals ,Urea ,Naphthyridines ,Rats, Wistar ,Benzoxazoles ,Morphine ,Chemistry ,General Neuroscience ,Antagonist ,Receptor antagonist ,Rats ,Substance Withdrawal Syndrome ,Orexin ,Endocrinology ,Locus coeruleus ,Locus Coeruleus ,Orexin Receptor Antagonists ,medicine.symptom ,Morphine Dependence ,medicine.drug - Abstract
The aim of this study was to evaluate the effects of orexin type-1 receptor (OX1R) antagonism in locus coeruleus (LC) nucleus on the development of morphine physical dependence in rats. Animals were rendered dependent on morphine by subcutaneous (s.c.) administration of morphine sulfate (6, 16, 26, 36, 46, 56 and 66 mg/kg, 2 ml/kg) at set intervals of 24 h for 7 days. Immediately before each morphine administration, the animals received intra-LC administration of SB-334867 (3 mM, 0.2 μl), a selective orexin type-1 receptor antagonist. On day 8, naloxone (3 mg/kg, i.p.) was injected and physical dependence was evaluated for 30 min. Our results showed that administration of OX1R antagonist before each morphine injection significantly decreased somatic signs of naloxone-induced morphine withdrawal syndrome, including defecation, wet-dog shake, diarrhea, jumping, scratching, and teeth chattering. These results suggest that the activation of OX1R in LC nucleus might be involved in the development of morphine dependency.
- Published
- 2014
5. Effect of different patterns of low-frequency stimulation on piriform cortex kindled seizures
- Author
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Javad Mirnajafi-Zadeh, Yaghoub Fathollahi, Mohammad Mohammad-Zadeh, and Parviz Ghorbani
- Subjects
Male ,Deep Brain Stimulation ,medicine.medical_treatment ,Perforant Pathway ,Electric Stimulation Therapy ,Stimulation ,Rats, Sprague-Dawley ,Epilepsy ,Seizures ,Piriform cortex ,Neural Pathways ,Kindling, Neurologic ,medicine ,Animals ,Low frequency stimulation ,Neurons ,business.industry ,Kindling ,General Neuroscience ,Pulse duration ,Olfactory Pathways ,medicine.disease ,Electrodes, Implanted ,Rats ,Intensity (physics) ,Treatment Outcome ,Anticonvulsant ,Anesthesia ,business - Abstract
Low-frequency stimulation (LFS) is an antiepileptic and antiepileptogenic electrical stimulation. In this study the effect of changes in some LFS (1 Hz, monophasic square wave) parameters (intensity, pulse duration and train duration) on piriform cortex kindled seizures was investigated both in fully kindled rats and during kindling acquisition. In fully kindled animals, application of different patterns of LFS immediately before kindling stimulation had no significant effect on seizure parameters. However, daily (15 min) application of LFS (0.1 ms pulse duration at intensity equal to after-discharge threshold (ADT) and 1 ms pulse duration at intensity equal to 1/4 ADT) during inter-seizure interval of 7 days significantly reduced the stage 5 duration of the next kindled seizure. Application of the same two LFS protocols for 3 days and 2 weeks had no effect on seizure parameters. The effect of LFS was also tested using different paradigms during kindling acquisition. When LFS (0.1 and 1 ms pulse duration, intensity equal to ADT and 1/4 ADT) was delivered daily after each kindling stimulation, it could significantly decrease after-discharge duration in various days during kindling development. In this experiment, only LFS with 0.1 ms pulse duration and intensity equal to ADT significantly delayed the appearance of seizure stages 1 and 2. According to obtained results, it may be concluded that in fully kindled rats application of different patterns of LFS before kindling stimulation has no anticonvulsant effect, but it can exert an inhibitory effect when applied during an inter-seizure interval of 7 days. In addition, LFS has antiepileptogenic effect during kindling acquisition. These effects depend on the applied LFS parameters (e.g. intensity, pulse duration and train duration).
- Published
- 2007
6. Serine/threonine protein phosphatases have no role in the inhibitory effects of low-frequency stimulation in perforant path kindling acquisition in rats
- Author
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Vahid Sheibani, Javad Mirnajafi-Zadeh, and mehdi sadegh
- Subjects
Male ,Calcineurin Inhibitors ,Perforant Pathway ,Stimulation ,Electric Stimulation Therapy ,Biology ,Pharmacology ,Inhibitory postsynaptic potential ,Tacrolimus ,chemistry.chemical_compound ,Okadaic Acid ,medicine ,Kindling, Neurologic ,Phosphoprotein Phosphatases ,Animals ,Protein Phosphatase 2 ,Enzyme Inhibitors ,Rats, Wistar ,Microinjection ,Epilepsy ,Kindling ,General Neuroscience ,Dentate gyrus ,Calcineurin ,Neural Inhibition ,Okadaic acid ,Perforant path ,Rats ,Disease Models, Animal ,medicine.anatomical_structure ,chemistry ,Neuroscience - Abstract
The use of low-frequency stimulation (LFS) as a therapy for epilepsy is currently being studied in experimental animals and patients with epilepsy. In the present study, the role of serine/threonine protein phosphatases in the inhibitory effects of LFS on perforant path kindling acquisition was investigated in rats. Animals were kindled by stimulation of perforant path in a stimulation using rapid kindling procedure (six stimulations per day). LFS (1Hz) was applied immediately after termination of each kindling stimulation. FK506 (1microM; i.c.v.), a serine/threonine protein phosphatase PP2B inhibitor and okadaic acid (1microM; i.c.v.), a serine/threonine protein phosphatases PP1/2A inhibitor, were daily microinjected into the left ventricle 10min before starting the stimulation protocol. Application of LFS retarded the kindling acquisition and delayed the expression of different kindled seizure stages significantly. In addition, LFS reduced the increment of daily afterdischarge duration during kindling development. Neither FK506 nor okadaic acid microinjection interfere with the antiepileptogenic effect of LFS on kindling parameters. Obtained results showed that activation of PP1/2A and PP2B, which play a critical role in LFS induced down-regulation of synaptic strength, had no role in mediating the inhibitory effects of LFS on perforant path kindling acquisition.
- Published
- 2008
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