Effects of acetyl-l-carnitine treatment and stress exposure on the nerve growth factor receptor (p75^NGFR) mRNA level in the central nervous system of aged rats

1. 1. There is growing evidence that the nerve growth factor protein (NGF), a neurotrophic factor for peripheral and central nervous system (CNS) neurons, may play a role in the modulation of the hypothalamo-pituitary-adrenocortical axis (HPAA). While NGF binding is decreased in rodent CNS after stress exposure, this reduction is prevented by treatment with Acetyl-L-Carnitine (ALCAR), a chemical substance able to prevent some degenerative events associated with aging. 2. 2. The authors studied the effect of cold stress on the low-affinity NGF receptor (p75^NGFR) mRNA levels in the basal forebrain and cerebellum of aged rats chronically treated with ALCAR. 3. 3. The present results show that ALCAR abolished the age-associated reduction of p75^NGFR mRNA levels in the basal forebrain of old animals, but did not affect the response to stress stimuli. 4. 4. Also, treatment with ALCAR mantained p75^NGFR mRNA levels in the cerebellum of old animals at levels almost identical to those observed in young control animals. 5. 5. These results suggest a neuroprotective effect for ALCAR on central cholinergic neurons exerted at the level of transcription of p75^NGFR. The restoration of p75^NGFR levels could increase trophic support by NGF of these CNS cholinergic neurons which are implicated in degenerative events associated with aging.