PLACENTAL TRANSFER AND TISSUE DISTRIBUTION OF MESCALINE-¹⁴C IN THE MOUSE

¹ Ensor Research Laboratory, William S. Hall Psychiatric Institute, Columbia, South Carolina

Albino mice (Swiss-Webster) on day 15 of gestation were injected i.p. with a tracer dose of mescaline-¹⁴C (36 µc/kg; 8.33 µmol/kg as free base). The distribution of unchanged mescaline-¹⁴C was examined in physiological fluids and in tissues on both sides of the placenta. At 15 minutes and 4 hours, the fetal brain levels were 1377 ± 123 and 567 ± 203 pmol/g, respectively; compared with mother brain, they were more than 2 and 4-rfold greater. The mescaline contents in plasma (3998 ± 303 pmol/ml) were highest at 15 minutes; those in placenta (4988 ± 535 pmol/g), whole fetus (2166 ± 228 pmol/g) and amniotic fluid (1639 ± 210 pmol/ml) were highest at 1 hour. Several maternal tissues, with the exception of brain, concentrated mescaline rapidly. Fifteen minutes after injection, time levels (as picomoles per gram) were: kidney, 22142 ± 1518; liver, 17626 ± 1347; lung. 16118 ± 1062; spleen, 13635 ± 910; heart, 8619 ± 564. The mescaline content of brain was among the lowest measured (peak 1 hour level, 957 ± 93 pmol/g). Smooth muscle (uterus) retained more mescaline than skeletal or cardiac muscle. At 4 hours. the uterus showed the highest concentration (2561 ± 369 pmol/g) of mescaline of all the tissues examined. About 50% of the injected dose was excreted in the urine during the first 3 hours, which indicates a rapid elimination of the drug.