Comparative pharmacological studies of melatonin receptors: mt1, mt2 and mt3/qr2. tissue distribution of mt3/qr2 11Abbreviations: MCA-NAT, methoxy-carbonylamino-N-acetyltrypta- mine, 2-[125I]-I-MCA-NAT, 2-[125I]-iodomethoxy-carbonylamino-N-acetyltryptamine; 2-IbMT, 2-iodo-N-butanoyl-5-methoxytryptamine; 4-P-PDOT, 4-phenyl-2-propionamido-tetraline; DH97, N-pentanoyl-2-benzyltryptamine; S20760, 5-methoxy-N-cyclopropanoyl-tryptamine; S24635, N-[2-(5-carbamoylbenzofuran-3-yl)ethyl]-acetamide; S25726, N-methyl-(3-{2-[(cyclopropylcarbonyl)-amino]ethyl}benzo[b]furan-5-yl)carbamate; S26553, N-methyl-{1-[2-(acetylamino)ethyl]-naphthalen-7-yl}carbamate.