5′-Guanidinonaltrindole (GNTI) is a selective kappa opioid receptor antagonist[1].
References
[1] Munro TA, et al. Long-acting κ opioid antagonists nor-BNI, GNTI and JDTic: pharmacokinetics in mice and lipophilicity. BMC Pharmacol. 2012 May 29;12:5. DOI:10.1186/1471-2210-12-5
