Modulation of olfactory-driven behavior by metabolic signals: role of the piriform cortex.
Olfaction is one of the major sensory modalities that regulates food consumption and is in turn regulated by the feeding state. Given that the olfactory bulb has been shown to be a metabolic sensor, we explored whether the anterior piriform cortex (aPCtx)-a higher olfactory cortical processing area-had the same capacity. Using immunocytochemical approaches, we report the localization of Kv1.3 channel, glucose transporter type 4, and the insulin receptor in the lateral olfactory tract and Layers II and III of the aPCtx. In current-clamped superficial pyramidal (SP) cells, we report the presence of two populations of SP cells: glucose responsive and non-glucose responsive. Using varied glucose concentrations and a glycolysis inhibitor, we found that insulin modulation of the instantaneous and spike firing frequency are both glucose dependent and require glucose metabolism. Using a plethysmograph to record sniffing frequency, rats microinjected with insulin failed to discriminate ratiometric enantiomers; considered a difficult task. Microinjection of glucose prevented discrimination of odorants of different chain-lengths, whereas injection of margatoxin increased the rate of habituation to repeated odor stimulation and enhanced discrimination. These data suggest that metabolic signaling pathways that are present in the aPCtx are capable of neuronal modulation and changing complex olfactory behaviors in higher olfactory centers.
['Al Koborssy|Dolly|D|', 'Palouzier-Paulignan|Brigitte|B|http://orcid.org/0000-0002-6941-4960', 'Canova|Vincent|V|', 'Thevenet|Marc|M|', 'Fadool|Debra Ann|DA|http://orcid.org/0000-0002-0546-3720', 'Julliard|Andrée Karyn|AK|http://orcid.org/0000-0002-3464-7529']
D000200:Action Potentials D000818:Animals D001522:Behavior, Animal D004192:Discrimination, Psychological D004734:Energy Metabolism D005260:Female D005947:Glucose D051275:Glucose Transporter Type 4 D006185:Habituation, Psychophysiologic D007004:Hypoglycemic Agents D007328:Insulin D051664:Kv1.3 Potassium Channel D008297:Male D051379:Mice D009812:Odorants D055696:Olfactory Perception D066195:Piriform Cortex D026902:Potassium Channel Blockers D017966:Pyramidal Cells D017208:Rats, Wistar D011972:Receptor, Insulin D012604:Scorpion Venoms D012903:Smell
Piriform Olfaction Kv1.3 Glucose Insulin GLUT4 Sniffing behavior