DESCRIPTION: Neuroactive peptides are the key players in a variety of human responses to pain, stress, hemorrhage, transfusion, orthostasis and anoxia, and are affecting the immune system The concentration of a specific neuropeptide in a certain system of the body can provide us with critical information on the state of health or disease. At present, there are no neuropeptide-specific electrodes available. We propose to develop an electrode for specific sensing of Substance P, a neuropeptide involved in the endogenous pain control in the central nervous system. We will be utilizing a novel approach of electrochemical registration of the conductivity changes, occurring in specifically designed conductive polymer matrix upon cooperative interaction of the immobilized on the matrix antibodies with selected neuropeptide. Specificity of such electrode can be designed by choosing the specificity of immobilized antibody. Phase I will be dedicated to the development and calibration of Substance P specific electrode in vitro. Phase I will be dedicated to miniaturization of the electrode and in vivo applications. An array of such electrodes with designed specificity will be able to detect several peptide neurotransmitters from the same site. PROPOSED COMMERCIAL APPLICATION: Electrodes, developed based on our approach, will represent a significant advance in the detection of peptide neurotransmitters, and will be a far better alternative to the immunoassays, which are currently used. Using an array of such electrodes with different specificity, it will be possible to detect several peptide neurotransmitters in vivo and from the same site, which will allow to study the interactive actions of neuropeptides on the neuroendocrine system.