In vivo electrochemical detection of 5-hydroxyindoles in rat cerebral cortex and spinal cord: differential effects of p-chloroamphetamine, probenecid and clorgyline.

Differential pulse voltammetry associated with carbon fiber microelectrodes was used to detect the 300 mV signal which is known to reflect the concentration of 5-hydroxyindoles in the spinal cord and cerebral neocortex of rats anesthetized with urethane or chloral hydrate. The intraperitoneal injection of p-chloroamphetamine resulted in an increase in the amplitude of the signal in the neocortex but not in the spinal cord. Administration of clorgyline did not consistently modify the signal monitored in the neocortex whereas it decreased in the spinal cord. Probenecid induced a larger increase in 5-hydroxyindoles in the neocortex than in the spinal cord. These results demonstrate that different parts of the serotonergic system might be differentially sensitive to drugs affecting serotonin metabolism.