The identification of risk factors that contribute to drug abuse is a major challenge in the development of drug abuse prevention and treatment strategies. Animal models of drug Self-administration have provided valuable information about drug reinforcement variables and response and environmental contingencies in adults as determinants of adult drug-taking behavior. Although prenatal and early postnatal experiences are likely determinants of later drug-taking behavior, little Is known about the effects of events during this important developmental period on later drug-taking behaviors. Precocial domestic fowl have provided valuable information about developmental determinants of behavior in a variety of different contexts. This biological model may provide valuable information on the effects of prenatal and early postnatal experiences on juvenile and adult drug self-administration. The proposed research is designed to determine if domestic fowl will self-administer cocaine. Twenty-eight-day old domestic fowl will be fitted with an intravenous catheter through which drug delivery can be made response contingent. Standard operant and control procedures will be used to determine if this model will acquire a key-pack response reinforced by delivery of IV cocaine and to explore schedule and drug reinforcement parameters. Genetic vulnerability to drug use will be assessed by using strains of fowl that display vastly different behavioral and pharmacologic characteristics. The proposed research is also designed to determine the impact of prenatal and perinatal exposure to cocaine on subsequent cocaine self-administration. Small amounts of cocaine will be administered to incubating eggs during the first, second, or third trimester, or to hatchlings during the first posthatch week. At four weeks posthatch animals will receive IV catheters. Alterations in cocaine reinforcement efficacy as a function of pre- or perinatal cocaine exposure will be evaluated by examining acquisition parameters, and after acquisition by requiring animals to key-peck at progressively higher response to reinforcement ratios from 1/1 to a ratio that the reinforcer will no longer support. Between hatch and the subsequent self-administ- ration tests, a sample of animals from each treatment group will be assessed for differences in activity and in vocalizations induced by brief social separation to determine if these measures will provide behavioral markers that correlate with subsequently assessed vulnerability to cocaine self-administration. The long-range aim of this research is to provide both the defining procedures and the empirical foundation of an avian model of drug self- administration with which the developmental determinants of drug abuse and their neurochemical correlates can be more fully explored.
| Cunnick, J E; Kojic, L D; Hughes, R A (1994) Stress-induced changes in immune function are associated with increased production of an interleukin-1-like factor in young domestic fowl. Brain Behav Immun 8:123-36 |
