Peptidergic neurons of subcortical white matter in aging and Alzheimer's brain

Most of the neurons in the subcortical white matter of the adult cerebrum are remnants of the transient subplate cortex which appears during early cortical development. The peptidergic neurons in the subcortical white matter, beneath the striate cortex were examined qualitatively and qualitatively with immunohistochemistry for substance P, cholecystokinin, somatostatin and neuropeptide Y in seven control patients and eight patients with Alzheimer's disease. The different peptidergic subcortical neurons still persisted in normal aging. In Alzheimer's disease, however, the substance P- and somatostatin-immunoreactive neurons were decreased in numbers and showed degenerative changes.

Increase in enkephalin-like immunoreactivity in hippocampi of adults with generalized epilepsy

The changes of opioid peptide reactivity in seizure activity have been well studied in animals. Increased enkephalin and dynorphin immunoreactivity in the hippocampi of animals are interpreted as the result of seizure induced mossy fibre sprouting. We studied the hippocampi of six patients with a history of long-standing grand mal seizures and six age-matched control patients with no history of epilepsy or neurologic disease, using frozen sections which were immunostained with antibodies against Leu-enkephalin and Met-enkephalin. The staining intensity in the CA3, CA4 and internal molecular layer of the dentate fascia in each case was quantified using optical densitometry image analysis. The CA3 and CA4 of the epileptic hippocampi showed highly significant increase in Leu-enkephalin-like immunoreactivity compared to the controls (P < 0.005) while the inner molecular layer showed only significant increase (P < 0.05). Met-Enkephalin-like immunoreactivity was only significantly increased in CA4 of the epileptic hippocampi (P < 0.05).