NE inputs to the piriform cortex

Compared to the bulb, our knowledge of monoaminergic inputs to PC is limited. LC neurons project heavily to PC (Mason and Corcoran, 1979, Fallon and Loughlin, 1982) and LC lesions decrease NE levels in PC by 77% (Fallon and Moore, 1978). Like the 

Both beta and alpha receptors are present in PC. In fact, both receptor types and their subunits are specifically localized in layer II of PC, while some studies see possible expression of the beta subtype in layer I (Nicholas et al. 1993 Wanaka et al. 1989 Sargent-Jones et al. 1985 Young and Kuhar, 1980a Palacios and Kuhar, 1982 Unner-stall et al. 1984). This pattern of adrenergic receptor localization suggests that noradrenergic terminals from the nucleus locus coeruleus make synaptic connectivity in this layer of PC. 

The physiological action of NE on PC neurons has received relatively little attention by comparison to numerous studies in other cortical regions. Sheldon and Aghajanian reported that NE caused excitation of putative interneurons located at the layer II/III border (Sheldon and Aghajanian, 1990). NE has also been shown to block the slow afterhyperpolarization in guinea-pig pyramidal cells (Constant and Sim, 1987), an effect similar to NE actions on hippocampal pyramidal neurons. 

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