Accessory olfactory bulb glomerular layer

Wilson K.C. and Raisman G. (1981). Estimation of numbers of vomeronasal synapses in the glomerular layer of the accessory olfactory bulb of the mouse at different ages. Brain Res 205, 245-254. 

Fig. 24. NE and 5-HT in the AOB. Darkfield photomicrographs through the accessory olfactory bulb showing similar dense labeling of noradrenergic (A) and serotonergic (B) fibers to mitral and granule cell layers of that structure while avoiding the glomerular layer.

S-HTja receptors. It is interesting that 5-HT,a and S-HTja receptor binding are both relatively low in the glomerular layer where there is substantial 5-HT innervation and possibly, synaptic input onto output cells (Liu and Shipley, in preparation). This could mean that a 5-HT receptor subtype other than the 5-HT, a or 5-HT2A is responsible for receiving 5-HT input in the glomeruli or it could mean there is a receptor/axon mismatch for 5-HT input in the bulb. Another 5-HT receptor subtype, S-HTjc is in low quantities in the olfactory bulb. The accessory olfactory bulb has not been analyzed adequately for the 5-HT receptor subtypes but it is clear that the mRNA for the S-HTja receptor is low to negligible in AOB (McLean et al. 1994). 

Figure 2. Sagittal section through the accessory olfactory bulb of an opossum stained with antibody to Goa. AOB=accessory olfactory bulb, AGL-anterior glomerular layer, PGL=posterior glomerular layer, Nl nerve layer, M/T=mitral/tufted cell layer, FCx=frontal cortex.

EP = exposed group (n = 3). OB = olfactory bulb OP = olfactory peduncle ON = olfactory nerve G1 = glomerular layer Epl = external plexi-form layer. Mi = mitral cell layer Ipl = internal plexiform layer GrO = granule cell layer of olfactory bulb Md = medullary layer GrA = granule cell layer of accessory olfactory bulb AOB = accessory olfactory bulb AOE = anterior olfactory nucleus external part AOL = anterior olfactory nucleus, lateral part lo = lateral tract. (Reprinted from Wang et alP 2007 Humana Press Inc.)... 

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