[ 99m Tc]4-Dithiocarbamato-N-benzylpiperidine [[[ 99m Tc]N(PNP)Pip-DTC]+] Drishty Satpati, MSc. Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085, drishtys@barc.gov.in Ketaki Bapat, PhD Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085, ketaki_bapat@hotmail.com Haladhar Deb Sarma, MVSc Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085, hdsarma@barc.gov.in Kanchan Kothari, PhD Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085, kanchan@scientist.com Meera Venkatesh, PhD Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085, meerav@barc.gov.in Sharmila Banerjee, PhD Bhabha Atomic Research Centre, Trombay, Mumbai, India 400085, sharmila@barc.gov.in Arvind Chopra, PhD National Center for Biotechnology Information, NLM, NIH, Bethesda, MD 20894, micad@ncbi.nlm.nih.gov Chemical name: [ 99m Tc]4-Dithiocarbamato-N-benzylpiperidine Abbreviated name: [[ 99m Tc]N(PNP)Pip-DTC] + Synonym: Agent Category: Compound Target: Sigma receptors Target Category: Receptor-ligand binding Method of detection: Single-photon emission computed tomography (SPECT), planar gamma imaging Source of Signal/Contrast: 99m Tc Activation: No Studies: • In vitro • Rodents Proposed structure of [[ 99m Tc]N(PNP)Pip-DTC] + . Background [PubMed] Sigma receptors belong to a unique family of proteins that are different from opioid and N- methyl-D-aspartate (NMDA) phencyclidine receptors ( 1 , 2 ). They are known to be involved in several disorders of the central nervous system such as schizophrenia, depression, and dementia (3-5). These receptors are classified into two subtypes, sigma-1 and sigma-2. Of the two subtypes, only the sigma-1 receptors are well studied and characterized. It has been demonstrated that [ 3 H](+)-pentazocine selectively labels only the sigma-1 sites, whereas di-o- tolyl guanidine (DTG) labels both the sigma-1 and sigma-2 receptors ( 6 , 7 ). Because sigma Molecular Imaging and Contrast Agent Database (MICAD)