Serotonergic fibers distribution

McLean JH, Shipley MT. 1987b. Serotonergic afferents to the rat olfactory bulb II. Changes in fiber distribution during development. J Neurosci 7 3029-3039. 

Our recent immunocytochemical studies indicate that the 5-HT innervation of the cortex exhibits less interlaminar specificity than NE terminals and is, in general, complimentary to that of NE inputs (Fig. 27). The serotonergic innervation of PC is very heavy by comparison to DA and NE. 5-HT fibers are especially heavy in layers I and III and the endopiriform nucleus. The density of 5-HT fibers progressively decreases in the deeper parts of layer III. Layer II by contrast, is sparsely innervated. 5-HT fibers in all layers are relatively short, with a tortuous, convoluted orientation and exhibit more varicosities than NE or DA fibers. As with NE, there is little variation of 5-HT fiber distribution or density at different rostrocaudal levels of PC. 

Neuromodulatory transmitter inputs to MOB. Darkfield photomicrographs showing the distribution of cholinergic (a), noradrenergic (b), and serotonergic (c) fibers revealed respectively with immunohistochemistry for choline acetyltransferase (ChAT), dopamine-jS-hydroxylase (DBH), and serotonin (5-HT). Reprinted from Handbook of Chem. Neuroanat. Integrated Sys. CNS, Vol. 12, Part III, Chapter III, The Olfactory System, M. Shipley et al., pp. 469-573, 1996, with permission from Elsevier, Ltd... 

Fig. 27. Modulatory transmitter systems in piriform cortex. Darkfield photomicrographs showing the distribution of dopaminergic (A), noradrenergic (B) and serotonergic (C) fibers in piriform cortex The axons are shown using antibodies to tyrosine hydroxylase (TH), dopamine-B-hydroxylase (DBH) and serotonin (5-HT) and immunocytochemistry. Dorsal is at the top and midline is to the left in all micrographs.

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