In the olfactory system, the glomeruli of the olfactory bulb define the first synapse processing odour information in the brain. Here, many synapses are established between olfactory sensory neurons (OSNs) and olfactory bulb neurons. Xenopus tropicalis tadpoles provide an excellent experimental platform to investigate the molecular mechanisms of synaptic transmission in vivo due to its experimental accessibility and transparency. We investigated long-lasting depolarizations (LLDs) occurring in the glomerular layer of the olfactory bulb by measuring changes in the local field potential. We recorded a single glomerulus taking advantage of the zHB9-GFP transgenic line. Odorant responses were obtained after ipsilateral stimulation of the olfactory epithelium with 200 µM methionine. The amplitude of the LLDs was related to the number of OSNs reaching glomeruli. The local application of CNQX and D-APV triggered a 80% decrease in the LLD’s amplitude, indicating that recordings reflected the activation of glutamatergic synapses. Unilateral olfactory nerve transection triggered a contralateral potentiation of LLDs that began 3h after injury and lasted for more than a week. Potentiation was circuit specific, as it was only observed upon unilateral damage of the olfactory pathway and, was of presynaptic origin. The mechanism causing the potentiation is not related to molecular pathways activated by reactive oxygen species present in tadpoles that mediate tissue repair. This study can drive to a better understanding of the bilateral processing of odour information in vertebrates as well as to the identification of mechanisms promoting the improvement of synaptic function after injury.