Summer Research

* Student(s): Eric Feldman , Kate Sanborn
Advisor: Herm Lehman

Title: NO + OA = NOOA?


Octopamine (OA) is an abundant invertebrate monoamine neurotransmitter in the invertebrates. Because OA and nitric oxide (NO) have been localized in the VUM neurons of Manduca sexta, we speculate that the free radical, nitric oxide, chemically interacts with OA in these neurons. Our project has two main objectives: first, to demonstrate that NO and OA are co-localized in the VUM neurons and second, to determine if NO is capable of altering the chemical structure of OA.

We have visualized NO using a histochemical procedure for the detection of NADPH diaphorase. NADPH is required for the enzyme necessary for NO synthesis, NO synthase, thus its distribution should reflect the distribution of NO synthase. In addition, we have used Western blots and immunocytochemistry using NO synthase antibodies. Direct exposure of catecholamines (compounds similar in structure to OA) to NO can alter the structure of catechols (Daveu et al., 1997). Using similar methods as Daveu et al., we have exposed OA to NO and studied the modification of the OA molecule using HPLC with electrochemical detection, capillary electrophoresis, and UV-spectrometry.

Our studies strongly indicate that OA is nitrated by NO, and future studies directed at the elucidation of the chemical structure of NO-OA are necessary.

Summer stipend support provided Bristol-Myers Squibb Foundation (KF) and Merck/AAAS (KS) grants to Hamilton College.