“Here, we sought to assess the effects of natural and synthetic cannabinoids on cholinergic bronchial contraction…
Delta-9-tetrahydrocannabinol, WIN55,212-2 and CP55,940 induced concentration-dependent inhibition of cholinergic contraction…
Conclusions and implications
Activation of prejunctional CB1-receptors appears to mediate the inhibition of electrical field stimulation-evoked cholinergic contraction in human bronchus.
This feature may explain the acute bronchodilation produced by marijuana smoking.”
http://onlinelibrary.wiley.com/doi/10.1111/bph.12597/abstract