CHANGES IN RECEPTOR LEVELS FOR THYROTROPIN-RELEASING-HORMONE, SEROTONIN, AND SUBSTANCE-P IN CERVICAL SPINAL-CORD OF WOBBLER MOUSE - A QUANTITATIVE AUTORADIOGRAPHY STUDY DURING EARLY AND LATE STAGES OF THE MOTONEURON DISEASE

Receptor levels for thyrotropin releasing hormone (TRH) measured by qu antitative autoradiography in the Wobbler mouse cervical spinal cord s how receptor losses that may relate to the inherited loss of motoneuro ns, most pronounced late (at Stage 4) in the motoneuron disease. An ag e-related decrease of TRH and serotonin (5-HT) receptors can be seen i n the ventral horn of the control specimens (normal phenotype litterma te and wild-type alike). However, this pattern is missing for substanc e P (SP) receptors from the wild-type specimens. Therefore the age-rel ated decrease of SP receptors detected in the Wobbler mouse strain may identify a strain-related defect in SP neuronal/receptor developmenta l patterns. A higher level of TRH receptors was measured in the Wobble r dorsal horn at an early stage (Stage 1) in the motoneuron disease co mpared with the control specimens. The data are discussed in relation to an aberrant neuronal sprouting that occurs around the degenerating motoneurons in the ventral horn during the course of the motoneuron di sease.