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. 2011;6(11):e26662.
doi: 10.1371/journal.pone.0026662. Epub 2011 Nov 18.

Decreased spontaneous eye blink rates in chronic cannabis users: evidence for striatal cannabinoid-dopamine interactions

Mikael A Kowal  1 , Lorenza S Colzato, Bernhard Hommel
Affiliations

Decreased spontaneous eye blink rates in chronic cannabis users: evidence for striatal cannabinoid-dopamine interactions

Mikael A Kowal et al. PLoS One. 2011.

Abstract

Chronic cannabis use has been shown to block long-term depression of GABA-glutamate synapses in the striatum, which is likely to reduce the extent to which endogenous cannabinoids modulate GABA- and glutamate-related neuronal activity. The current study aimed at investigating the effect of this process on striatal dopamine levels by studying the spontaneous eye blink rate (EBR), a clinical marker of dopamine level in the striatum. 25 adult regular cannabis users and 25 non-user controls matched for age, gender, race, and IQ were compared. Results show a significant reduction in EBR in chronic users as compared to non-users, suggesting an indirect detrimental effect of chronic cannabis use on striatal dopaminergic functioning. Additionally, EBR correlated negatively with years of cannabis exposure, monthly peak cannabis consumption, and lifetime cannabis consumption, pointing to a relationship between the degree of impairment of striatal dopaminergic transmission and cannabis consumption history.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Years of cannabis exposure as a function of spontaneous eye blink rate per minute.
Figure 2
Figure 2. Peak monthly cannabis consumption (in joints) as a function of spontaneous eye blink rate per minute.
Figure 3
Figure 3. Lifetime cannabis consumption (in joints) as a function of spontaneous eye blink rate per minute.
See this image and copyright information in PMC

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