Relative numbers of immunoreactive neurons in submucous (SG) and myenteric (MG) ganglia in colon for calcitonin gene-related peptide (CGRP), cocaine- and amphetamine-related transcript (CART), galanin (Gal), gastrin-releasing peptide (GRP), neuropeptide Y (NPY), nitric oxide synthase (NOS), somatostatin (som), substance P (SP), and vasoactive intestinal peptide (VIP), expressed as % of human neuronal protein HuC/D-immunoreactive neurons, from rats treated with four sessions of saline (C) or buserelin (B). Cell-counting was performed on cross- and longitudinally-cut, whole-wall cryo sections, doubly immunostained for HuC/D and respective neuropeptide or NOS. With the exception of submucous som-immunoreactive neurons, which showed a tendency to increase after buserelin treatment (p = 0.062), no differences in any of the neuronal subpopulations were found between groups. Results are presented as individual data and medians. Statistical analyses were performed by the Mann-Whitney U-test, C = 5–6 rats and B = 10–11 rats.