evidence pointing to the presence of opiate receptors in the rabbit iris was obtained in an in vivo study of the effects on the pupil of the intraocular injection of morphine ( 10 -- 100 micrograms ) and d-ala2-met-enkephalinamide ( d-ala-e ) ( 5 -- 50 micrograms ) .
C0022077
iris
C0034121
pupil