title: comparative study of opiate and enkephalin receptors on lower vertebrates and higher vertebrates.
mesh_terms: D000557:Ambystoma / Q000378:metabolism*; D000558:Ambystoma mexicanum / Q000378:metabolism*; D000818:Animals; D004745:Enkephalins / Q000378:metabolism; D005048:Etorphine / Q000378:metabolism; D008675:Metamorphosis, Biological; D010999:Pleurodeles / Q000378:metabolism*; D051381:Rats / Q000378:metabolism*; D011957:Receptors, Opioid; D012455:Salamandridae / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D004745:Enkephalins; D011957:Receptors, Opioid; D005048:Etorphine