≥97% (HPLC)

Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
MDL number:
PubChem Substance ID:

Quality Level


≥97% (HPLC)

UniProt accession no.

storage temp.


SMILES string




InChI key


Gene Information

mouse ... Pnoc(18155)

Amino Acid Sequence

Phe-Cys-Tyr-Trp-Orn-Thr-Pen-Thr-NH2 [Disulfide Bridge: 2-7]

General description

D-Pen-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) is a selective cyclic μ-opioid receptor antagonist.


CTOP has been used:
  • to study the anxiogenic effects induced by CTOP in mice and rat.
  • to study the effect of μ-opioid antagonist, CTOP on the bovine milk-derived LF (BLF)-induced analgesia.
  • to determine whether μ-opioid receptors act cooperatively with 5-hydroxytryptamine (5-HT1A) receptors to regulate the behaviors generated in the elevated T-maze (ETM).

Biochem/physiol Actions

Selective ligand for μ-opioid receptors.
D-Pen-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) inhibits acute morphine-induced hypermotility and analgesic effect of morphine in a dose-dependent manner in vivo.


Somatostatin analog

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis

Certificate of Origin

Kate M Wassum et al.
The Journal of neuroscience : the official journal of the Society for Neuroscience, 31(5), 1591-1599 (2011-02-04)
The decision to perform, or not perform, actions known to lead to a rewarding outcome is strongly influenced by the current incentive value of the reward. Incentive value is largely determined by the affective experience derived during previous consumption of...
Andrew C Eschenroeder et al.
Glia, 60(1), 125-136 (2011-10-18)
Although the classical function of myelin is the facilitation of saltatory conduction, this membrane and the oligodendrocytes, the cells that make myelin in the central nervous system (CNS), are now recognized as important regulators of plasticity and remodeling in the...
He-Min Yang et al.
Frontiers in systems neuroscience, 14, 51-51 (2020-08-28)
Aim: To examine the effects of fentanyl, a potent mu-opioid receptor (MOR) agonist, on-air puff-evoked responses in Purkinje cells (PCs), and molecular layer interneurons (MLIs) using in vivo patch-clamp recordings in anesthetized mice. Methods: Male mice 6-8 weeks-old were anesthetized...
Chronic pain induces anxiety with concomitant changes in opioidergic function in the amygdala.
Narita M
Neuropsychopharmacology, 31(4), 739-750 (2006)
Elena I Varlinskaya et al.
Alcoholism, clinical and experimental research, 33(6), 991-1000 (2009-03-24)
Ethanol consumption is considerably elevated during adolescence. Attractiveness of alcohol for humans during the adolescent developmental period is based, in part, on its ability to induce social facilitation--a facilitation of social interactions not only evident in human adolescents but also...

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