Testing-Chamber Familiarity Influenced THC Responses in a Historical Rabbit Study

A 1978 rabbit experiment found that familiarity with the testing chamber influenced acute and repeated THC responses. Its combined behavioral and EEG measurements show why experimental setting belongs in an account of tolerance.

Familiar and unfamiliar groups were compared

New Zealand White rabbits were either adapted to the chamber or tested without that prior adaptation. Both groups received daily intravenous THC for twelve days. Researchers recorded motor-cortex and hippocampal EEG alongside posture and activity under vehicle and on the first and final THC days.

Tolerance involved more than one measurement

The authors reported tolerance to behavioral and EEG effects, with environmental influences on acute and chronic responses. EEG is an electrical measurement, while standing, sprawling and activity are observable behaviors. The abstract does not provide enough detail to assign the same magnitude or direction of environmental influence to every measure.

Context dependence is not complete protection

The experiment does not establish that familiar surroundings eliminate cannabinoid effects. Nor does it isolate learning as the only mechanism of adaptation. Prior chamber exposure can change the response without showing that receptor or pharmacokinetic adaptation is absent.

The useful conclusion is that tolerance findings should identify the setting in which exposure and testing occurred. This rabbit protocol does not establish a human impairment test or show that experienced cannabis users function normally in every environment. Familiarity, repeated dosing and the actual endpoint remain separate variables.

Related: interpreting cannabis tolerance claims.

Research cited

Martin P; Consroe P. Tolerance to delta9-tetrahydrocannabinol in adapted and nonadapted rabbits. Pharmacology, biochemistry, and behavior (1978). doi:10.1016/0091-3057(78)90352-0. Findings discussed from the study abstract.