1996/12/01 by Hans Tjälve, Jörgen Henriksson, Jonas Tallkvist +2 · 2 citations
Neuroscience · Medicine · Chemistry · #Olfactory and Sensory Function Studies #Medicinal Plants and Neuroprotection #Electrochemical Analysis and Applications #Olfactory system #Olfactory epithelium #Neurotoxicity #Central nervous system #Olfactory mucosa #Olfactory bulb #Nasal administration #Spinal cord #Chemistry #Neuroscience #Anatomy #Medicine #Biology #Toxicity #Internal medicine #Pharmacology
paper · doi:10.1111/j.1600-0773.1996.tb00021.x
openalex publication_date 1996/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/05/21
In the olfactory epithelium the primary olfactory neurones are in contact with the environment and via the axonal projections they are also connected to the olfactory bulbs of the brain. Therefore, the primary olfactory neurones provide a pathway by which foreign materials may gain access to the brain. In the present study we used autoradiography and gamma spectrometry to show that intranasal instillation of manganese (54Mn2+) in rats results in initial uptake of the metal in the olfactory bulbs. The metal was then seen to migrate via secondary and tertiary olfactory pathways and via further connections into most parts of the brain and also to the spinal cord. Intranasal instillation of cadmium (109Cd2+) resulted in uptake of the metal in the anterior parts of the olfactory bulbs but not in other areas of the brain. This indicates that this metal is unable to pass the synapses between the primary and secondary olfactory neurones in the bulbs. Intraperitoneal administration of 54Mn2+ or 109Cd2+ showed low uptake of the metals in the olfactory bulbs, an uptake not different from the rest of the brain. Manganese is a neurotoxic metal which in man can induce an extrapyramidal motor system dysfunction associated with occupational inhalation of manganese-containing dusts or fumes. We propose that the neurotoxicity of inhaled manganese is related to an uptake of the metal into the brain via the olfactory pathways. In this way manganese can circumvent the blood-brain barrier and gain direct access to the central nervous system.