"Octopamine and Nitric Oxide Metabolites: Do They Have a Physiological Action?"

Anna Arnold
Under the Supervision of Professor H.K. Lehman

Hamilton College

2003-2004

I. Introduction (Abbreviated)
II. Methods (Abbreviated)
III. Video Documentation
IV. References (Abbreviated for page)

I. Introduction

Based on the movies embedded below and the quantification of specific behavioral responses, it is apparent that 4’hydroxyacetophenone has a physiological action within the nervous system of the Manduca sexta. Specifically, 4'hydroxyacetophenone affects the ability of the larva right itself and its proleg withdrawal response.

I am basing my assumptions concerning the actions of the ketone on a particular molecular scenario. This scenario involves the activation of nitric oxide synthase by the influx of calcium ions during an action potential. Nitric oxide synthase subsequently produces excess nitric oxide, which then transverses the cellular membrane of octopamanergic vesicles. Because nitric oxide is highly reactive and has been shown to modify compounds similar to octopamine, the gas may ultimately modify octopamine to form novel compounds that are released into the synapse and have specific post-synaptic actions (Figure 1) (De la Bretche, M.L., et.Al., 1994). Nitrite (nitric oxide donor) interacts with octopamine to form 4’hydroxyacetophenone in vitro (Arnold, A., Hankowski, K., 2002).

Figure 1. Molecular scenario describing the interaction of nitric oxide and octopamine to form compounds that have a specific postsynaptic action.

II. Methods

Larvae were injected at the third abdominal section, above the second proleg, dorsal and 45 degress from the midline, with 0.2 mL of either the control (1:5 DMSO:1XSaline), 0.1 M Octopamine (Sigma), or 0.1 M 4'hydroxyacetophenone (Sigma). Periodically, both the ability of the larva to right itslef and proleg withdrawal response were tested. Righting ability is characterized by the time it takes the larva to roll upright with all prolegs on the surface after placed on its side. Proleg withdrawal response is characterized by the percent of the larva's prolegs that respond to a sharp stimulus. The following movies served as a data source for this quantification.

III. Video Documentation

I edited the following movies in IMovie. Each is a representation of the larva's reaction to the injection of the indicated compound over a specific time course.

 

This web page is acting as an appendix to my biochemistry/molecular biology senior thesis entitled: "Octopamine and Nitric Oxide Metabolites: Do They Have a Physiological Action?"

 

IV. References

Arnold, A., Hankowski, K. Unpublished Data. 2002.

De la Bretche, M.L., Servy, C., L'enfant, M., and Ducrocq, C. “Nitration of catecholamines with nitrogen oxides in mild conditions: a hypothesis for the reactivity of NO
in physiological systems.” Tetrahedron Letters, 35(39) (1994): 7231-7232.