The alpha 2-agonist clonidine suppresses seizures, whereas the alpha 2-antagonist idazoxan promotes seizures--a microinfusion study in amygdala-kindled kittens. 1994

M N Shouse, and M Bier, and J Langer, and O Alcalde, and M Richkind, and R Szymusiak
VAMC, Sepulveda, CA 91343.

This is the first report showing that local, in vivo microinfusion of alpha 2-adrenoreceptor agonists and antagonists have contrasting effects on amygdala-kindled seizure susceptibility. Microinfusions (1 microliter) of the alpha 2-agonist clonidine (CLON) and of the alpha 2-antagonist idazoxan (IDA) were made over 1 min through cannulae adjacent to stimulating electrodes in five amygdala-kindled kittens. Order of administered drugs (CLON vs. IDA) and dosages (n = 3 each) was partly counterbalanced. Focal and convulsive seizure thresholds were evaluated 10-12 min post-infusion and compared to thresholds obtained during two, interspersed control conditions (vehicle control: 1 microliter microinfusion of sterile saline; sham control: needle insertion only). CLON significantly elevated focal and generalized seizure thresholds, whereas IDA significantly reduced seizure thresholds when compared to controls. Magnitude of effects was dose-dependent. Results confirm and extend previous findings which employed unlocalized, in vivo manipulations to show that norepinephrine is a potent antiepileptic agent in the amygdala kindling preparation.

UI MeSH Term Description Entries
D007696 Kindling, Neurologic The repeated weak excitation of brain structures, that progressively increases sensitivity to the same stimulation. Over time, this can lower the threshold required to trigger seizures. Kindlings, Neurologic,Neurologic Kindling,Neurologic Kindlings
D008297 Male Males
D008845 Microinjections The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes. Microinjection
D002415 Cats The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801) Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D003000 Clonidine An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION. Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
D003292 Convulsants Substances that act in the brain stem or spinal cord to produce tonic or clonic convulsions, often by removing normal inhibitory tone. They were formerly used to stimulate respiration or as antidotes to barbiturate overdose. They are now most commonly used as experimental tools. Convulsant,Convulsant Effect,Convulsant Effects,Effect, Convulsant,Effects, Convulsant
D004146 Dioxanes Compounds that contain the structure 1,4-dioxane.
D004567 Electrodes, Implanted Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body. Implantable Electrodes,Implantable Stimulation Electrodes,Implanted Electrodes,Implanted Stimulation Electrodes,Electrode, Implantable,Electrode, Implantable Stimulation,Electrode, Implanted,Electrode, Implanted Stimulation,Electrodes, Implantable,Electrodes, Implantable Stimulation,Electrodes, Implanted Stimulation,Implantable Electrode,Implantable Stimulation Electrode,Implanted Electrode,Implanted Stimulation Electrode,Stimulation Electrode, Implantable,Stimulation Electrode, Implanted,Stimulation Electrodes, Implantable,Stimulation Electrodes, Implanted
D004594 Electrophysiology The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D004830 Epilepsy, Tonic-Clonic A generalized seizure disorder characterized by recurrent major motor seizures. The initial brief tonic phase is marked by trunk flexion followed by diffuse extension of the trunk and extremities. The clonic phase features rhythmic flexor contractions of the trunk and limbs, pupillary dilation, elevations of blood pressure and pulse, urinary incontinence, and tongue biting. This is followed by a profound state of depressed consciousness (post-ictal state) which gradually improves over minutes to hours. The disorder may be cryptogenic, familial, or symptomatic (caused by an identified disease process). (From Adams et al., Principles of Neurology, 6th ed, p329) Epilepsy, Grand Mal,Epilepsy, Major,Grand Mal Seizure Disorder,Major Motor Seizure Disorder,Seizure Disorder, Tonic Clonic,Convulsions, Grand Mal,Cryptogenic Tonic-Clonic Epilepsy,Epilepsy, Tonic-Clonic, Cryptogenic,Epilepsy, Tonic-Clonic, Familial,Epilepsy, Tonic-Clonic, Symptomatic,Familial Tonic-Clonic Epilepsy,Seizure Disorder, Grand Mal,Seizure Disorder, Major Motor,Symptomatic Tonic-Clonic Epilepsy,Tonic Clonic Convulsions,Tonic-Clonic Convulsion Disorder,Tonic-Clonic Convulsion Syndrome,Tonic-Clonic Seizure Disorder,Tonic-Clonic Seizure Syndrome,Convulsion Disorder, Tonic-Clonic,Convulsion Disorders, Tonic-Clonic,Convulsion Syndrome, Tonic-Clonic,Convulsion Syndromes, Tonic-Clonic,Convulsion, Grand Mal,Convulsion, Tonic Clonic,Convulsions, Tonic Clonic,Cryptogenic Tonic Clonic Epilepsy,Cryptogenic Tonic-Clonic Epilepsies,Disorder, Tonic-Clonic Convulsion,Disorder, Tonic-Clonic Seizure,Disorders, Tonic-Clonic Convulsion,Disorders, Tonic-Clonic Seizure,Epilepsies, Cryptogenic Tonic-Clonic,Epilepsies, Familial Tonic-Clonic,Epilepsies, Symptomatic Tonic-Clonic,Epilepsies, Tonic-Clonic,Epilepsy, Cryptogenic Tonic-Clonic,Epilepsy, Familial Tonic-Clonic,Epilepsy, Symptomatic Tonic-Clonic,Epilepsy, Tonic Clonic,Familial Tonic Clonic Epilepsy,Familial Tonic-Clonic Epilepsies,Grand Mal Convulsion,Grand Mal Convulsions,Grand Mal Epilepsy,Major Epilepsies,Major Epilepsy,Seizure Disorder, Tonic-Clonic,Seizure Disorders, Tonic-Clonic,Seizure Syndrome, Tonic-Clonic,Seizure Syndromes, Tonic-Clonic,Symptomatic Tonic Clonic Epilepsy,Symptomatic Tonic-Clonic Epilepsies,Syndrome, Tonic-Clonic Convulsion,Syndrome, Tonic-Clonic Seizure,Syndromes, Tonic-Clonic Convulsion,Syndromes, Tonic-Clonic Seizure,Tonic Clonic Convulsion,Tonic Clonic Convulsion Disorder,Tonic Clonic Convulsion Syndrome,Tonic Clonic Seizure Disorder,Tonic Clonic Seizure Syndrome,Tonic-Clonic Convulsion Disorders,Tonic-Clonic Convulsion Syndromes,Tonic-Clonic Epilepsies,Tonic-Clonic Epilepsies, Cryptogenic,Tonic-Clonic Epilepsies, Familial,Tonic-Clonic Epilepsies, Symptomatic,Tonic-Clonic Epilepsy,Tonic-Clonic Epilepsy, Cryptogenic,Tonic-Clonic Epilepsy, Familial,Tonic-Clonic Epilepsy, Symptomatic,Tonic-Clonic Seizure Disorders,Tonic-Clonic Seizure Syndromes

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