Catecholamines in human dental pulp. A combined immunohistochemical and chromatographic study

Pharmacological studies have suggested that nerve-released catecholamines may play an important role in the regulation of vascular tone and in the modulation of sensory nerve activity in animal teeth. We have used tyrosine hydroxylase-immunohistochemistry to detect catecholamine-producing cells in human dental pulp and high performance liquid chromatography to identify and quantitate catecholamines in this tissue. Tyrosine hydroxylase-immunoreactivity was confined to a sub-population of nerve fibres that were mainly localized around blood vessels. Considerable concentrations of norepinephrine (17.8 +/- 3.75 pg/mg tissue) and much lower concentrations of dopamine and epinephrine (0.27 +/- 0.10 and 0.19 +/- 0.11 pg/mg, respectively) were measured in all samples examined. It is suggested that catecholamines in human dental pulp are exclusively contained in nervous structures that are mainly associated with blood vessels and that norepinephrine is the candidate neurotransmitter of these nerve fibres. These data provide the basis to further studies addressed to clarify the possible functions of catecholamines in human dental pulp during physiological as well as inflammatory situations.