Modulation of Dendrodendritic Interactions in the Rat Olfactory Bulb by Locus Coeruleus Stimulation

Observations that noradrenaline induces enduring enhancement of the efficacy of a second transmitter in central synapses are intriguing and have attracted considerable attention, as the process may serve as a neuronal substrate for learning and memory. This may be true for synapses in the olfactory bulb (OB), as the significance of noradrenergic centrifugal inputs to the OB in olfactory learning has been noted in a number of models [1]. Noradrenergic terminals in the OB originate in the locus coeruleus (LC) [2]. However, the role of LC noradrenergic neurons in OB function has not been fully clarified. We therefore examined the effect of stimulation of the LC on mitral-granule cell interactions in the rat OB.