Penfluridol blockade of apomorphine: dependence of duration on species and endpoint

Changes in body temperature after administration of amino acids, peptides, dopamine, neuroleptics and related agents

Drugs may alter body temperature by acting on any component of the thermoregulatory system. These components include heat production, heat conservation and heat loss effectors and their efferent pathways, thermosensors and their afferent pathways and neurons within the central nervous system that coordinate thermoregulatory effector activities. A thermostat is often thought to be involved although thermoregulation can be explained by models that do not incorporate a thermostat. An action on a particular component can be assessed by determining the effect of a drug on body temperature over a range of environmental temperatures and by observation and measurement of associated changes in effector activities. A scheme for such assessment is presented along with examples of its use. The study of drug-induced changes in body temperature has expanded greatly within the past decade. The primary purpose of this review is to provide a readily available source of information on interactions between certain drugs and the thermoregulatory system. Extensive tables are presented of body temperature changes after administration of amino acids, peptides, dopamine and related agents, phenothiazine neuroleptics and also phenothiazines that lack neuroleptic activity, butyrophenones, diphenylbutylpiperidines such as pimozide and miscellaneous neuroleptics. The information tabulated includes the species used, route of administration and dose of drugs, the environmental temperature at which the experiments were performed, the number of tests, the direction and magnitude of body temperature change and remarks on the presence of special conditions, such as age or lesions, or on the influence of other drugs, such as antagonists, on the response to the primary drug. Most of the cited literature was published since 1965.

Comparative effects of penfluridol on circling behavior and striatal DOPAC and serum prolactin concentrations in the rat

A single s.c. injection of penfluridol (3 mg/kg) to rats elevated serum concentrations of prolactin for more than 96 h whereas it increased striatal concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) and inhibited apomorphine-induced circling behavior for less than 48 h. The dose of penfluridol needed to elevate serum concentrations of prolactin (0.1 mg/kg) was less than that required to elevate striatal concentrations of DOPAC (1 mg/kg) or inhibit apomorphine-induced circling (3 mg/kg). Furthermore, the penfluridol-induced increase of striatal DOPAC was more susceptible to reversal by apomorphine than was the increase of serum prolactin concentrations. These results suggest that the dopamine receptors in the pituitary, which are normally activated by dopamine released from tuberoinfundibular neurons, are more sensitive to the blocking actions of systemically administered penfluridol than are dopamine receptors in the striatum.