Endogenous opiates: 1999

This paper is the twenty-second installment of the annual review of researc h concerning the opiate system. It summarizes papers published during 1999 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; toleranc e and dependence; learning, memory, and reward; eating and drinking; alcoho l and other drugs of abuse; sexual activity, pregnancy, and development; me ntal illness and mood; seizures and other neurologic disorders; electrical- related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregu lation; and immunologic responses. (C) 2000 Elsevier Science Inc. All right s reserved.