Cerebral uptake of nicotine and of amino acids.
Nicotine is among the compounds that enter the brain very rapidly (blood-flow-limited). It also leaves the brain rapidly; by five minutes, 90% exits, an exit somewhat slower than that of water. In spite of rapid exit, brain levels remain higher than levels in blood over a wide range of blood concentrations. Nicotine enters the fetal circulation from the maternal blood; it enters fetal brain but to a smaller extent than adult brain. Nicotine entry is different from that of amino acid: No interaction of amino acid transport and nicotine could be detected. Most close analogs have no effect on nicotine uptake, but at higher concentrations nicotine uptake is saturable. Nicotine and morphine mutually inhibit each other's uptake. The results suggest an uptake compartment (lipid space) for nicotine shared by morphine.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D008431:Maternal-Fetal Exchange; D051379:Mice; D009538:Nicotine / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats
D000596:Amino Acids; D009538:Nicotine