1. A method for identifying antagonists of known odorants, comprising the steps of: contacting a primary culture of dissociated olfactory neurons with a quantity of a known odorant, said quantity of known odorant having the ability to excite said olfactory neurons, said olfactory neurons: (a) comprising at least about 85% of the cells in said primary culture of olfactory neurons, (b) demonstrating responsiveness in culture to 1 nM IBMP, to between about 1 and about 10 uM citralva, and to between 1 and about 10 uM isovaleric acid, (c) expressing vimentin, olfactory marker protein and neuron-specific enolase, and (d) not expressing glial fibrillary acidic protein, S-100 protein, keratin, or neurofilament protein, said expression being assessed by immunohistochemistry or by Western blotting; determining a first level of excitation of the neurons in the presence of said quantity of the known odorant; contacting said primary culture of olfactory neurons with a mixture consisting of said quantity of the known odorant and a putative antagonist; determining a second level of excitation of the neurons in the presence of said mixture; and comparing said first and second excitation levels, an antagonist being identified when the second level of excitation is less than the first level of excitation.