With the benzodiazepine derivative midazolam, at any point in time the time course and intensity of effects on operant behavior correspond to the serum concentration of the drug. In the most recent study, under the direction of Dr. Chyan Lau, these investigators imposed delays between the administration of midazolam and the beginning of an operant test session. Some animals experienced the delay in their home cage and another group in the operant test chamber. Active Versus Passive Drug Administration and the HPA Axis Recent research has shown that the neurochemical and behavioral effects of cocaine depend upon whether the drug is self-administered, i.e. active administration, or delivered independently of responding, i.e. passive administration. For example, during withdrawal, both neurotransmitter levels and neurotransmitter turnover rates differ for active versus passive cocaine administration.
Mortality is higher following passive delivery of cocaine.
Research by R. Galici et. In the study conducted in the laboratory of Dr. Charles France at Louisiana State University, plasma corticosterone levels in rats were higher following active than following passive cocaine administration. Galici, R., Pechnick, R.N., Poland, R.E., and France, C.P. Eur. Dr. Felipe Gomez, in collaboration with Drs. Both groups received the same number of morphine administrations.