RTI-121 explained

(–)-2β-Carboisopropoxy-3β-(4-iodophenyl)tropane (RTI-4229-121, IPCIT) is a stimulant drug used in scientific research, which was developed in the early 1990s.^[1] RTI-121 is a phenyltropane based, highly selective dopamine reuptake inhibitor^[2] and is derived from methylecgonidine. RTI-121 is a potent and long-lasting stimulant, producing stimulant effects for more than 10 hours after a single dose in mice^[3] which would limit its potential uses in humans, as it might have significant abuse potential if used outside a medical setting. However RTI-121 occupies the dopamine transporter more slowly than cocaine, and so might have lower abuse potential than cocaine itself.^[4]

Uses

RTI-121 is mainly used in scientific research into the dopamine reuptake transporter. It is more selective for the dopamine transporter than other DAT radioligands such as β-CIT, and so has less nonspecific binding and produces "cleaner" images.^{[5] [6]} Various radiolabelled forms of RTI-121 (with different radioactive isotopes of iodine used depending on the application) are used in both humans and animals to map the distribution of dopamine transporters in the brain.^{[7] [8]}

Legal status

RTI-121 not specified as controlled substance in any country as of 2007. Some jurisdictions such as the United States, Australia, and New Zealand, however, might however consider RTI-121 to be a controlled substance analogue of cocaine on the grounds of its related chemical structure.

See also

• RTI-55
• List of cocaine analogues
• List of Phenyltropanes

Notes and References

1. Scheffel U, Dannals RF, Wong DF, Yokoi F, Carroll FI, Kuhar MJ . Dopamine transporter imaging with novel, selective cocaine analogs . NeuroReport . 3 . 11 . 969–72 . November 1992 . 1482766 . 10.1097/00001756-199211000-00005 .
2. Boja JW, Cadet JL, Kopajtic TA, Lever J, Seltzman HH, Wyrick CD, Lewin AH, Abraham P, Carroll FI . 6 . Selective labeling of the dopamine transporter by the high affinity ligand 3 beta-(4-[125I]iodophenyl)tropane-2 beta-carboxylic acid isopropyl ester . Molecular Pharmacology . 47 . 4 . 779–86 . April 1995 . 7723739 .
3. Fleckenstein AE, Kopajtic TA, Boja JW, Carroll FI, Kuhar MJ . Highly potent cocaine analogs cause long-lasting increases in locomotor activity . European Journal of Pharmacology . 311 . 2–3 . 109–14 . September 1996 . 8891589 . 10.1016/0014-2999(96)00423-2 .
4. Stathis M, Scheffel U, Lever SZ, Boja JW, Carroll FI, Kuhar MJ . Rate of binding of various inhibitors at the dopamine transporter in vivo . Psychopharmacology . 119 . 4 . 376–84 . June 1995 . 7480516 . 10.1007/BF02245852 . 20022021 .
5. Scanley BE, al-Tikriti MS, Gandelman MS, Laruelle M, Zea-Ponce Y, Baldwin RM, Zoghbi SS, Hoffer PB, Charney DS, Wang S . 6 . Comparison of [123I]beta-CIT and [123I]IPCIT as single-photon emission tomography radiotracers for the dopamine transporter in nonhuman primates . European Journal of Nuclear Medicine . 22 . 1 . 4–11 . January 1995 . 7698153 . 10.1007/BF00997241 . 20406294 .
6. Scanley BE, Gandelman MS, Laruelle M, Al-Tikriti MS, Baldwin RM, Zoghbi SS, Hoffer PB, Wang S, Neumeyer JL, Innis RB . 6 . [123I]IPCIT and [123I]beta-CIT as SPECT tracers for the dopamine transporter: a comparative analysis in nonhuman primates . Nuclear Medicine and Biology . 27 . 1 . 13–21 . January 2000 . 10755641 . 10.1016/s0969-8051(99)00083-9 .
7. Chen NH, Ding JH, Wang YL . Characterization of [125I]RTI-121 binding to dopamine transporter in vitro . Zhongguo Yao Li Xue Bao = Acta Pharmacologica Sinica . 18 . 2 . 115–20 . March 1997 . 10072960 .
8. Lever JR, Scheffel U, Stathis M, Seltzman HH, Wyrick CD, Abraham P, Parham K, Thomas BF, Boja JW, Kuhar MJ, Carroll FI . 6 . Synthesis and in vivo studies of a selective ligand for the dopamine transporter: 3 beta-(4-[125I]iodophenyl) tropan-2 beta-carboxylic acid isopropyl ester ([125I]RTI-121) . Nuclear Medicine and Biology . 23 . 3 . 277–84 . April 1996 . 8782237 . 10.1016/0969-8051(95)02074-8 . free .