Induction of catalepsy in mice
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Transcript of Induction of catalepsy in mice
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Induction of Catalepsy in Mice/Rats
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What is Catalepsy??
• Catalepsy is a nervous condition characterized by muscular rigidity and fixity of posture regardless of external stimuli, as well as decreased sensitivity to pain.
• Waxy flexibility and cerea flexibilitas
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Causes of Catalepsy
• Catalepsy is a symptom of certain nervous disorders or conditions such as Parkinson's disease and epilepsy.
• It is also a characteristic symptom of cocaine withdrawal. • It can be caused by schizophrenia treatment with anti-
psychotics such as haloperidol and by the anaesthetic ketamine.
• Protein kinase A has been suggested as a mediator of cataleptic behaviour.
• Other causes of catalepsy include reuptake inhibitors of adrenergic neurotransmitters such as Reserpine.
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Symptoms of Catalepsy
• Symptoms include: rigid body, rigid limbs, limbs staying in same position when moved (waxy flexibility), no response, loss of muscle control, and slowing down of bodily functions, such as breathing
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Induction of Catalepsy in Mice/Rats• Neurotensin administered intra cerebroventricularly
(ICV 0.5, 1.0 and 2.0 μg) produced catalepsy in a dose-dependent fashion in mice.
• A significant effect was observed at 2.0 μg and a maximal effect 2–3 h after injection.
• The NT-induced catalepsy was inhibited by pretreatment with atropine, trihexyphenidyl or biperiden (each drug, 0.8–5.0 mg/kg, IP), anticholinergic drugs, and L-DOPA (100, 200 mg/kg, IP).
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• Pinch-induced catalepsy is readily obtained in mice following repeated administration of strong pinches at the scruff of the neck.
• This catalepsy outlasted the pinch by minutes and was more easily induced on retests 48 hr after the initial acquisition tests.
• Repetitive tail pinches and/or exposure to the testing procedure without pinches also resulted in immobility; however, this was weak in magnitude and short in duration.
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• Haloperidol 1mg/kg IP has been used many a times to induce catalepsy in rats.
• Mice : Haloperidol 2mg/kg IP
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Observation
• Catalepsy, defined as a reduced ability to initiate movement and a failure to achieve correct posture, is measured by the bar test.
• Mice are positioned so that their hindquarters are on the bench and their forelimbs rest on a 1-cm diameter horizontal bar that is 4 cm above the bench.
• Mice are judged to be cataleptic if they maintain this position for 30s or more.
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• The length of time for which the mouse maintains this position is recorded with a stopwatch with a maximum duration of 180s.
• This procedure is performed 30 min after the administration of haloperidol (2 mg/kg, IP).
• If the mouse holds the position for 30s or more then catalepsy is said to be induced.
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Catalepsy
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Why induce catalepsy?
• To observe the effects of dopamine blocking agents on motor system
• To get an idea of clinical symptom of catalepsy• To produce models for testing newer drugs for
diseases like Parkinson’s disease which are based on dopamine hypothesis.