Open AccessCharacteristics of Learning and Memory Impairment Induced by ⊿9-Tetrahydrocannabinol in Rats
Author(s) -
Kenichi Mishima,
Nobuaki Egashira,
Nobue Hirosawa,
Megumi Fujii,
Yoshiaki Matsumoto,
Katsunori Iwasaki,
Michihiro Fujiwara
Publication year - 2001
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.87.297
Subject(s) - radial arm maze , water maze , memory impairment , working memory , psychology , memory consolidation , impaired memory , tetrahydrocannabinol , audiology , morris water navigation task , memory disorder , anesthesia , neuroscience , developmental psychology , cognitive disorder , cognition , medicine , cognitive impairment , hippocampus , cannabinoid , receptor
We investigated the characteristics of delta9-tetrahydrocannabinol (THC)-induced impairment of learning and memory using an 8-arm radial maze task, a water maze, a visual discrimination task with 2 figures and a passive avoidance test in rats. THC (6 mg/kg, i.p.) impaired spatial memory in the standard task of the 8-arm radial maze. THC (4-6 mg/kg, i.p.) selectively impaired working memory in a reference and working memory task of the 8-arm radial maze. Even at a dose of 10 mg/kg, THC did not impair spatial memory in the water maze. In addition, THC at a dose of 6 mg/kg, which had inhibitory effects in the 8-arm radial maze, did not affect performance in the visual discrimination task. These results indicate that at low doses (2-6 mg/kg), THC may not produce visual function abnormalities. THC impaired retrieval (6 mg/kg, i.p.) as well as acquisition (10 mg/kg, i.p.) in the passive avoidance test. The consolidation process was also impaired by i.c.v. injection (100 microg), but not i.p. injection (6-10 mg/kg) of THC. These results suggest that THC-induced impairment of spatial memory is based on the selective impairment of working memory through its effects on acquisition and retrieval processes.