Chronic alcohol consumption increases cyclo (His-Pro)-like immunoreactivity in the rat brain.

Administration of histidyl-proline diketopiperazine (cyclo (His-Pro)) to rats attenuates ethanol-induced sleep. To understand the role played by cyclo (His-Pro) in the pathophysiology of prolonged alcohol consumption, we have measured the distribution of this peptide in brains of control and alcohol-treated rats. The data show that prolonged alcohol consumption increases the concentration of cyclo (His-Pro) in hypothalamic as well as extrahypothalamic brain. These changes may reflect a physiologic adaptation of the brain during alcohol consumption.