Calcium-Binding Proteins in the Mesencephalic Trigeminal Nucleus of the Cat

The presence and distribution of two calcium-binding proteins (CaBPs), parvalbumin (PV) and calbindin D-28k (CB) were immunohistochemically examined in the mesencephalic trigeminal nucleus (MTN) of normal untreated cats and after peripheral nerve injury to the masseteric nerve. Under normal conditions, many PV-immunoreactive (IR) neurons were distributed throughout the whole rostrocaudal extent of MTN, although those in its pontine part were predominant. All immunopositive cells were medium-to-large in size and round-to-oval in appearance. A large number of CB-IR neurons was also found in the intact MTN. Following unilateral peripheral axotomy of the masseteric nerve, the distribution of both CaBPs in the MTN contralaterally to the transection side was very similar to that in untreated animals. However, by combining retrograde labeling of axotomized neurons with immunohistochemistry, a pattern of CaBPs-like immunoreactivity (LI) that changed with time was established. For example, on the side ipsilateral ...