Table 1.

Summary of systemic CBD effects on contextual fear memory processing in male rats (Δ9-THC, Δ9-tetrahydrocannabinol; BDNF, brain derived neurotrophic factor; CB1R, cannabinoid type1 receptor; ERK1/2, extracellular signal-regulated kinase1/2; i.p., intraperitoneal; PL, prelimbic; SHR, spontaneously hypertensive rat; TrkB, tyrosine receptor kinase B).

Strain	Dosing details	Effect	Possible mechanism(s)	References
Wistar	10 mg/kg, i.p., pre-retrieval	Anxiolytic (↓ fear expression)	Not tested	Resstel et al., 2006
Lister hooded	10 mg/kg daily for 14 days, i.p., pre-acquisition and -retrieval	Anxiogenic (↑ fear expression) and/or potentiated fear conditioning	↓ hippocampal BDNF and TrkB expression, ↓ frontal cortex phospho-ERK1/2 levels	ElBatsh et al., 2012
Wistar and SHR	1.0–15 mg/kg, i.p., pre-acquisition	Anxiolytic (↓ fear expression) and/or disrupted fear memory formation (in Wistar rats only)	Not tested	Levin et al., 2012
Wistar	3.0–30 mg/kg, i.p., post-retrieval	Disrupted memory reconsolidation (bell-shaped dose-response curve)	Indirect CB1R activation	Stern et al., 2012
Wistar	10 mg/kg, i.p., post-retrieval	Disrupted memory reconsolidation	Not tested	Gazarini et al., 2014
Wistar	10 mg/kg, i.p., post-retrieval	Disrupted memory reconsolidation	Indirect CB1R activation in PL	Stern et al., 2014
Wistar	1.0 mg/kg + Δ9-THC 0.1 mg/kg, i.p., post-retrieval	Disrupted memory reconsolidation	Not tested	Stern et al., 2015
Lister hooded	10 mg/kg, i.p., pre-extinction (after weak or strong fear conditioning)	Impaired extinction with weak fear conditioning and enhanced extinction with strong fear conditioning	Not tested	Song et al., this issue