Hippocampal neurotrophic factor: characterization and response to denervation

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• The rat hippocampus contains an acidic macromolecular neurotrophic factor (NTF).
• This NTF supports the survival of cultured chick ciliary ganglion cells.
• Hippocampal NTF concentration increases significantly from birth to adulthood.

Purpose of the Study:

• To investigate the regulation and origin of hippocampal neurotrophic factor (NTF).
• To determine how extrinsic inputs and intrinsic neuronal integrity affect hippocampal NTF levels.

Main Methods:

• Lesioning studies involving entorhinal cortex, locus coeruleus, contralateral hippocampus, and septum.
• Kainic acid treatment to destroy intrinsic hippocampal neurons.
• Administration of methotrexate to inhibit gliosis.

Main Results:

• Disruption of extrinsic inputs (except from the septum) increased hippocampal NTF concentration.
• Destruction of intrinsic hippocampal neurons led to a significant increase in hippocampal NTF.
• Methotrexate suppressed the lesion-induced rise in NTF, indicating reduced gliosis.

Conclusions:

• Hippocampal NTF concentration increases with age and is modulated by extrinsic inputs.
• Evidence suggests a glial origin for hippocampal NTF.
• The factor's production is linked to gliosis, a reactive process in glial cells.