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Behavior in animals is produced by the central nervous system (CNS) and is strongly influenced by hormones that can act within the CNS, on neuromuscular targets and on visceral organs. The ultimate goal of my research is to understand the mechanisms through which hormones modulate behavior. My research program takes an integrated approach to this problem by studying behavior at the level of whole animals, identifying hormones and neurotransmitters that underlie behavior, and uncovering the mechanisms of action of hormones and transmitters at the cellular and sub-cellular levels. My students and I use invertebrates as model systems for study. Much of our work has focused on “FMRFamide-like peptides”, which appear to be present in all animals. These chemicals regulate the heart, vascular tissues, nerve cells, muscle cells and visceral organs.
My students and I are currently examining the biochemical processes that allow specific neuropeptides to enhance communication between neurons and their target cells at chemical synapses. We want to identify the second messenger systems that mediate the ability of neuropeptides to increase transmitter release from presynaptic cells and to increase the responsiveness of postsynaptic cells to neuropeptides. We will also determine whether different peptides play essentially the same role and, thus, are essentially redundant, or whether different peptides act on specific cells. In addition to these cellular approaches, my students also examine aggressive interactions between members of the same species, with the aim of determining whether or not such behaviors are modified by neuropeptide hormones. We recently found that crayfish respond to reflective surfaces, and that their behavioral responses depend on dominance status. By combining cellular and behavioral approaches, we hope to provide a more complete picture of how biochemical and cellular actions of hormones are integrated to produce and/or modify behavior.
At the moment, the behavioral experiments are being performed using crayfish, and experiments involving second messengers, calcium imaging and synaptic modulation are being performed with fruitflies. We plan to perform behavioral experiments with fruitflies in the very near future, since this will allow us to exploit several genetic tools.
May, H., Mercier, A.J. (2007) Responses of dominant and subordinate crayfish to mirrors diverge with time of pairing. J. Exp. Biol. (accepted, 2 Oct., 2007)
Mercier, J., Doucet, D., Retnakaran, A. (2007) Molecular physiology of crustacean and insect neuropeptides. J. Pesticide Science (accepted 15 July, 2007)
May, H., Mercier, A.J. (2006) Behavioural responses of crayfish to reflection depend on dominance status. Can. J. Zool. 84: 1104-1111.
Drozdz, J.K., Viscek, J., Brudzynski, S.M., Mercier, A.J. (2006) Behavioral responses of crayfish to a reflective environment . Journal of Crustacean Biology 26: 463-473.
Badhwar, A., Weston, A.D., Murray, J., Mercier, A.J. (2006) A role for cyclic nucleotide monophosphates in synaptic modulation by a crayfish neuropeptide. Peptides 27: 1281-1290.
Dunn, T.W., Mercier, A.J. (2005) Synaptic modulation by a Drosophila neuropeptide is motor neuron specific and requires CaMKII activity. Peptides 26: 269-276.
Fixon-Owoo, S., Sharma, J., Williams, K., Lowe, M., Klose, M., Mercier, A.J., Atkinson, J. (2003) Preparation and biological assessment of hydroxycinnamic acid amides of polyamines: Analogues of the naturally occurring conjugates of coumaric acid with di- and polyamines. Phytochem. 63: 315-334
Wrong, A.D., Sammahin, M., Richardson, R., Mercier, A.J. (2003) Pharmacological properties of glutamate receptors associated with the crayfish hindgut. J. Comp. Physiol. 189: 371-378
Dunn, T. and Mercier, A.J. (2003) Synaptic modulation by a neuropeptide depends on temperature and extracellular calcium. J. Neurophysiol. 89: 1807-1814.
Mercier, A.J., Friedrich, R. and Boldt, M. (2003) Physiological functions of FMRFamide-like peptides (FLPs) in Crustaceans. Microscopy Research Tech. 60, 313-324.
Lee, J. and A.J. Mercier. (2002) Differential effects of neuropeptides on circular and longitudinal muscles of the crayfish hindgut. Peptides 23:1751-7.
Klose, M.K., Atkinson, J.K. and Mercier, A.J. (2002) Effects of a hydroxy-cinnamoyl conjugate of spermidine on arthropod neuromuscular junctions. J. Comp. Physiol. A. 187, 945-952.
Jonz, M.G., Riga, E., Mercier, A.J. & Potter, J.W. (2001) Root diameter influences cyst size in Heterodera schachtii (Heteroderidae). Nematologia Mediterranea. 29:169-171.
Jonz, M.G., Riga, E., Mercier, A.J. & Potter, J.W. (2001) Effects of 5-HT (serotonin) on reproductive behaviour in Heterodera schachtii (Nematoda). Can. J. Zool. 79, 1727-1732.
Jonz, MG, Riga, E, Mercier, AJ & Potter JW. (2001) Partial isolation of a water soluble pheromone component from the sugar beet cyst nematode, Heterodera schachtii, using a novel bioassay. Nematology 3, 55-64.