Differential effects of THC or CBD-rich cannabis extracts on working memory in rats

P Fadda, L Robinson, W Fratta, R G Pertwee, G Riedel

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Abstract

Cannabinoid receptors in the brain (CB1) take part in modulation of learning, and are particularly important for working and short-term memory. Here, we employed a delayed-matching-to-place (DMTP) task in the open-field water maze and examined the effects of cannabis plant extracts rich in either Delta(9)-tetrahydrocannabinol (Delta(9)-THC), or rich in cannabidiol (CBD), on spatial working and short-term memory formation in rats. Delta(9)-THC-rich extracts impaired performance in the memory trial (trial 2) of the DMTP task in a dose-dependent but delay-independent manner. Deficits appeared at doses of 2 or 5 mg/kg (i.p.) at both 30 s and 4 h delays and were similar in severity compared with synthetic Delta(9)-THC. Despite considerable amounts of Delta(9)-THC present, CBD-rich extracts had no effect on spatial working/short-term memory, even at doses of up to 50 mg/kg. When given concomitantly, CBD-rich extracts did not reverse memory deficits of the additional Delta(9)-THC-rich extract. CBD-rich extracts also did not alter Delta(9)-THC-rich extract-induced catalepsy as revealed by the bar test. It appears that spatial working/short-term memory is not sensitive to CBD-rich extracts and that potentiation and antagonism of Delta(9)-THC-induced spatial memory deficits is dependent on the ratio between CBD and Delta(9)-THC. (C) 2004 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)1170-1179
Number of pages10
JournalNeuropharmacology
Volume47
DOIs
Publication statusPublished - 2004

Keywords

  • cannabis extract
  • THC
  • cannabidiol
  • working memory
  • water maze
  • rat
  • SHORT-TERM-MEMORY
  • IMPAIRS SPATIAL MEMORY
  • MORRIS WATER MAZE
  • LONG-TERM
  • ORAL DELTA(9)-TETRAHYDROCANNABINOL
  • LIMBIC SYSTEM
  • PERFORMANCE
  • DELTA-9-TETRAHYDROCANNABINOL
  • TASK
  • MICE

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