P. Josephbravo et al., PYROGLUTAMYL PEPTIDASE-II ACTIVITY IS NOT IN THE PROCESSES OF BULBOSPINAL TRHERGIC NEURONS, Neuroscience letters, 178(2), 1994, pp. 243-246
Pyroglutamyl peptidase II (PPII) is a neuronal ectoenzyme involved in
released thyrotropin-releasing hormone (TRH) inactivation. In an attem
pt to define if it is present in the pre or postsynaptic membrane, we
induced neuronal degeneration of serotonin-TRHergic cells that project
from raphe nuclei to the spinal cord. 2-4 weeks after intracisternal
injection of 5, 7-dihydroxytryptamine, TRH levels decreased over 70% i
n the cervical, thoracic or lumbar regions of spinal cord. In contrast
, no change of PPII activity was observed. Longer times after injectio
n (6-8 weeks), a 59-66% increase in activity was detected in the lumba
r region. These data suggest that PPII is not localized in these TRHer
gic neurons but probably in the target cells.