Distribution of parvalbumin immunoreactivity in the cat brain stem.

We studied the distribution of parvalbumin-immunoreactive cell bodies and fibers in the cat brain stem. A high or moderate density of perikarya containing parvalbumin was observed in the periaqueductal gray, interpeduncular nucleus, nucleus of the trapezoid body, superior and inferior colliculi, and in the substantia nigra. The nucleus ruber, cuneiform nucleus, preolivary nucleus, retrorubral nucleus, paracentral division of the tegmental reticular nucleus, central and lateral tegmental fields, and the pericentral division of the dorsal tegmental nucleus had the lowest density of immunoreactive cell bodies. Moreover, a high or moderate density of parvalbumin immunoreactive processes was visualized in the nucleus ruber, substantia nigra, superior and inferior colliculi, periaqueductal gray, nucleus sagulum, cuneiform nucleus, Kölliker-Fuse nucleus, nucleus of the trapezoid body, vestibular nuclei, dorsal motor nucleus of the vagus, and in the lateral reticular nucleus. Finally, a few immunoreactive fibers were observed in the pontine gray, nucleus coeruleus, marginal nucleus of the brachium conjunctivum, nucleus of the solitary tract, inferior olive, and in the tegmental fields.