Neurons which contained Irinotecan hydrochloride loukoumasomes were strictly adrenergic. This was particularly apparent in the mixed adrenergic/ cholinergic male pelvic ganglion. Although loukoumasomes were relatively uniformly-distributed among throughout pelvic ganglia, loukoumasomecontaining neurons often occurred in a distinct region within the stellate ganglion close to the exit point of the cardiac nerve. These cells were larger, rounder and more densely packed than those in loukoumasome-negative regions of the ganglia, and we found that we could reliably predict the location of loukoumasomes based on these morphological characteristics. The size, shape and intraganglionic position of loukoumasomepositive stellate ganglion neurons correspond precisely with a subpopulation of large round neurons innervating the left ventricle of the heart. In both stellate and pelvic ganglia, a subset of large, round neurons co-express neuropeptide Y and calbindin-D28k. Several previous findings strongly suggest that this particular sympathetic neurochemical phenotype represents the population of neurons which contains loukoumasomes. First, the location and shape of loukoumasome-containing neurons in the stellate ganglion is identical to those which express both calbindin and NPY. Second, in pelvic ganglia, where all TH-positive neurons contain NPY, approximately half of the TH-positive neurons also express calbindin, corresponding very well with the proportion of noradrenergic neurons containing loukoumasomes. Third, all superior cervical ganglion neurons projecting to the pineal gland express both NPY and calbindin, and occur with a frequency, roughly equivalent to what we found for noradrenergic neurons containing loukoumasomes. Succinylsulfathiazole Indeed, we found that, without exception, loukoumasome-containing neurons in the pelvic and stellate ganglia expressed both NPY and calbindin. In pelvic ganglia where nearly all noradrenergic cells contain loukoumasomes, neurons are unipolar.We therefore asked whether those in stellate ganglia which contained loukoumasomes were also structurally simpler than those which did not.