Estimation of central activity of hydroxyproline--the amino acid characteristic for collagen degradation products.

The central activity of hydroxyproline - the amino acid characteristic for collagen degradation products was studied. The levels of urinary and serum hydroxyproline are elevated in many disturbances, among them is a mental deficiency connected with hydroxyprolinemia. Previous studies showed that the mixture of collagen degradation products is biologically active and exerts and effect on central nervous system. In our study hydroxyproline significantly decreased the psychomotor activity of rats in Lat's test, enhanced amphetamine stereotypy in lower doses, and enhanced catalepsy in one of used doses. It prolonged the time of thiopental sleeping. The pentylenetetrazole seizures latency was not significantly prolonged and duration of seizures was shorter after injection (icv) of hydroxyproline. Our investigations show, that hydroxyproline is the active amino acid in the mixture of collagen degradation products and may be responsible for central activity of this mixture.