Disruption of sensitization to methylphenidate by a single administration of MK-801
| Autor: | Alan C. Swann, Osvaldo Gaytan, Nachum Dafny |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Single administration
Male Saline injection Pharmacology Motor Activity General Biochemistry Genetics and Molecular Biology Rats sprague dawley Rats Sprague-Dawley Activity monitoring medicine Animals Motor activity General Pharmacology Toxicology and Pharmaceutics Sensitization Methylphenidate business.industry General Medicine Single injection Rats medicine.anatomical_structure Anesthesia Dizocilpine Maleate Stereotyped Behavior business Excitatory Amino Acid Antagonists medicine.drug |
| Zdroj: | Life sciences. 70(19) |
| ISSN: | 0024-3205 |
| Popis: | Blockade of sensitization to methylphenidate by a single injection of MK-801 was investigated using a computerized activity monitoring system. Male Sprague-Dawley rats were housed in test cages and motor activity was recorded continuously for 16 days. After 2 days of baseline recording and a saline injection on day 3, the rats were randomly divided into four experimental groups. All received 2.5 mg/kg of methylphenidate (s.c.) once a day from days 4 to 9, then after five days of no treatment, they were re-challenged with 2.5 mg/kg of methylphenidate on day 15. One group received only methylphenidate, while the other three groups also received a single i.p. injection of MK-801 (0.30 mg/kg) either 24 h (day 3) or 1 h prior to the first of the six methylphenidate injections (day 4), or 1 h prior to the second methylphenidate injection (day 5). A single injection of MK-801 on day 4 (1 h prior to methylphenidate) blocked the development of sensitization to methylphenidate, since a sensitized response could not be elicited six days after cessation of repeated methylphenidate administration (day 15). However, sensitization to methylphenidate still occurred in the groups receiving MK-801 (0.30 mg/kg) on day 5, indicating that the mechanism by which a single injection of MK-801 disrupts sensitization to methylphenidate is sensitive to timing and is not a direct long-term effect. In conclusion, a single injection of MK-801 persistently blocks the development of sensitization to methylphenidate only if it is given with methylphenidate on the first day of the repetitive treatment phase. |
| Databáze: | OpenAIRE |
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