Characterization of Pyrethroids on Sperm Voltage-Sensitive Calcium Channels (2005 - Present)

Investigator:  Steven Symington, Salve Regina University
Mentor:  Kim Boekelheide, Brown University 

Abstract:  The immediate aim of this project is to determine the effect of pyrethroid insecticides on calcium homeostasis in mouse caudal epididymal sperm and the effect of these compounds on viability. Recent results indicate that voltage-sensitive calcium channels are target sites for pyrethroid insecticides. Thus, in the proposed studies at Salve Regina University, a primarily undergraduate university, the hypothesis that pyrethroid insecticides modify calcium homeostasis via modification of voltage-sensitive calcium channels will be investigated. Specifically, we will use mouse caudal epididymal sperm to examine the effects of pyrethroids on sperm motility, calcium influx, and the acrosome reaction; processes that are regulated by intracellular calcium influx via voltage-sensitive calcium channels. It is expected that pyrethroids will act as antagonists and will result in sterility due to inhibition of calcium influx via calcium channels associated with mammalian spermatozoa. 

A combination of behavioral and fluorescent biochemical assays in addition to more rigorous electrophysiological methods will be used to assess the effects of pyrethroids on voltage-sensitive calcium channels using mouse caudal epididymal sperm. These methods have previously been shown to be useful in the assessment of ion permeability changes induced by channel antagonists. 

Pyrethroids are the predominant class of insecticides used to control several medically important insects that vector human diseases. These potent insecticides have a wide spectrum of use and are effective in controlling a variety of insect pests in the prevention of insect-mediated human and animal disease transmission. The increased spread of the aforementioned diseases will likely result in increased efforts to control medically important insects and increased exposure situations for individuals in urban environments. Thus, it is critical that these insecticides by evaluated for the potential adverse effects on reproduction.

Publications

2008 - 2009

Clark, J.M., Symington, S.B. 2008. Neurotoxic implications of the agonistic action of CS-syndrome pyrethroids on Cav2.2. Pest Manage Science, 64, 628-638.

2007 - 2008

Clark, J.M., Symington, S.B. 2007. Pyrethroid action at calcium channels: Neurotoxicological implications. Invert Neurosci., 7, 3-16.

Presentations

2006 - 2007

Symington, S.B., Frisbie, R.K., Kim, H.J., Clark, J.M. 2006. Phosphorylation of threonine 422 alters the action of deltamethrin on Cav2.2. 11th International Congress of Pesticide Chemistry, Kobe, Japan, August 6-11.

Catlin, N., Alves, A., Clark, J.M., Symington, S.B. 2006. The effects of deltamethrin on mammalian voltage-sensitive calcium channels. 1st Biennial National IDeA Symposium of Biomedical Research Excellence (NISBRE). Washington, DC, July 20-22.

Symington, S.B., Frisbie, R.K., Kim, H.J., Clark, J.M. 2006. Effect of Cav2.2 phosphorylation on the in vitro action of deltamethrin. 36th Society of Neuroscience, Atlanta, GA, October 14-18.

Kong, S., Hestand, K., Jamal, A., Symington, S.B. 2006. Effects of insecticides on mouse spermatozoa viability. 64th Annual Eastern New England Biology Conference. Simmons College, Boston, MA, April 23.

Kong, S., Hestand, K., Jamal, A., Symington, S.B. 2006. The effects of pyrethroid and organochlorine insecticides on mouse spermatozoa viability. 1st Biennial National IDeA Symposium of Biomedical Research Excellence (NISBRE). Washington, DC, July 20-22.