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Mephedrone (4‐methylmethcathinone) and d‐methamphetamine improve visuospatial associative memory, but not spatial working memory, in rhesus macaques
Author(s) -
Wright, Jr MJ,
Vandewater SA,
Angrish D,
Dickerson TJ,
Taffe MA
Publication year - 2012
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.2012.02091.x
Subject(s) - spatial memory , psychology , working memory , stimulant , cathinone , cambridge neuropsychological test automated battery , methamphetamine , cognitive psychology , neuroscience , hippocampus , psychomotor learning , cognition , audiology , medicine , amphetamine , psychiatry , dopamine
BACKGROUND AND PURPOSE The novel cathinone derivative 4‐methylmethcathinone (4‐MMC; mephedrone) is increasingly popular with recreational users. Little scientific information is available but users report both entactogen‐like and classic stimulant‐like subjective properties. A recent study in humans reported psychomotor speed improvement after intranasal 4‐MMC suggesting classic stimulant properties. Limitations of the user group (which was impaired on some tasks) prompt controlled laboratory investigation. EXPERIMENTAL APPROACH Adult male rhesus monkeys were trained to perform tasks from the non‐human primate Cambridge Neuropsychological Test Automated Battery, which assess spatial working memory, visuospatial associative memory, learning and motivation for food reward. Test of bimanual motor coordination and manual tracking were also included. The subjects were challenged with 0.178–0.56 mg·kg −1 4‐MMC and 0.056–0.56 mg·kg −1 d‐methamphetamine (MA), i.m., in randomized order for behavioural evaluation. KEY RESULTS A pronounced improvement in visuospatial memory and learning was observed after the 0.32 mg·kg −1 dose of each compound, this effect was confirmed with subsequent repetition of these conditions. Spatial working memory was not improved by either drug, and the progressive ratio, bimanual motor and rotating turntable tasks were all disrupted in a dose‐dependent manner. CONCLUSIONS AND IMPLICATIONS These studies show that 4‐MMC produces behavioural effects, including improvements in complex spatial memory and learning that are in large part similar to those of MA in non‐human primates. Thus, the data suggest that the effects of 4‐MMC in monkeys can be classified with classical psychomotor stimulants.