Effect of capsaicin upon fluoride sensitive acid phosphatases in selected ganglia and spinal cord and upon neuronal size and number in dorsal root ganglion.

A quantitative method for the analytical separation of the fluoride sensitive acid phosphatases of rat spinal cord and peripheral nervous tissues into tartrate-sensitive and tartrate-resistant forms (TSAP and TRAP, respectively) is described. Evidence supporting the use of L-(+)-tartrate rather than fluoride as an inhibitor is presented. The method is used for the quantitative description of the consequences of neonatal capsaicin treatment, and the results appear to justify the attribution of the TRAP activity to the capsaicin sensitive neurons. In the first experiment, rats were killed at weekly intervals after neonatal capsaicin treatment. In controls, both TRAP and TSAP activities in dorsal root ganglia (DRG) increased during the second postnatal week and remained constant thereafter. At all ages (1-4 weeks) TRAP activity was reduced 50-60% in capsaicin-treated DRG. Reduction of TSAP activity was much less. In a second experiment, rats were treated neonatally with capsaicin or vehicle (control) and allowed to grow to adulthood (4 months). TRAP activity was found to be decreased 38% in the dorsal half of the lumbar spinal cord (L3-L5), decreased 33% in nodose ganglion, and unchanged in superior cervical ganglion of the capsaicin treated animals. TSAP activity was unchanged in dorsal spinal cord and superior cervical ganglion and decreased 33% in nodose ganglion. The number of neurons in C8 DRG was found to be reduced 28% in capsaicin treated animals. The loss appeared to be among the small neurons. The number of large neurons was actually increased in ganglia from capsaicin-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)