Glutamate-like immunoreactivity in axon terminals from the olfactory bulb to the piriform cortex

L. Hennequet, J. Gondra, J. Sendino and F. Ortega

Department of Neurosciences, Faculty of Medicine and Dentistry, Faculty of Farmacy, Basque Country University, Bilbao, Vizcaya, Spain

Offprint requests to: Dr. Fernando Ortega Higuera, M.D. Department of Neurosciences, Faculty of Medicine and Dentistry, Basque Country University, Apdo. 699, 48080 Bilbao, Vizcaya, Spain

Summary. A highly specific anti-glutamate monoclonal antibody, mAb2D7, was used together with light and electron microscopy to elucidate the role played by the amino acid glutamate in the projection from the olfactory bulb to the piriform cortex in the rat. By light microscopy, glutamate-like immunoreactivity was observed in neuronal cell bodies and in the neuropil of the piriform cortex. Double labelling experiments which involved injections of wheat germ agglutinin-horse-radish peroxidase into the olfactory bulb and a post-embedding immunogold method for electron microscopy revealed anterogradely labelled terminals making asymmetric synaptic contacts on dendrites in the piriform cortex which contained high levels of glutamate as assessed by quantification. These results further support a role for glutamate as a neurotransmitter in the efferent pathway of the rat olfactory bulb. Histol. Histopathol. 13, 683-687 (1998)

Key words: Glutamate, Olfactory cortex, Horseradish peroxidase

DOI: 10.14670/HH-13.683