VASOACTIVE INTESTINAL POLYPEPTIDE AND ACETYLCHOLINE COEXIST WITH NEUROPEPTIDE-Y, DOPAMINE-BETA-HYDROXYLASE, TYROSINE-HYDROXYLASE, SUBSTANCE-P OR CALCITONIN GENE-RELATED PEPTIDE IN NEURONAL SUBPOPULATIONS IN CRANIAL PARASYMPATHETIC GANGLIA OF RAT

Immunohistochemistry has been used to demonstrate that neuropeptide Y, dopamine-beta-hydroxylase, calcitonin gene-related peptide or substance P are co-localized with vasoactive intestinal polypeptide and choline acetyltransferase in subpopulations of neurons in cranial parasympathetic ganglia of rat. These comprise the ciliary, sphenopalatine, otic, glossopharyngeal-vagal and internal carotid ganglia. In the ciliary and glossopharyngeal-vagal ganglia tyrosine hydroxylase is also found in such neurons. The findings emphasize that the combined localization of dopamine-beta-hydroxylase and neuropeptide Y or the presence of tyrosine hydroxylase is not exclusively a marker for peripheral adrenergic neurons. Further, the co-localization of calcitonin gene-related peptide and substance P is not a decisive indication that a neuron is sensory in nature. It is discussed whether the presence of the enzymes and peptides other than vasoactive intestinal polypeptide is a remnant of a different expression during ontogenesis or indicates target-specific functions in the adult.