Cardiovascular and hormonal responses to hyperthermic stress in cocaine addicts after a long period of abstinence

Abstract

In order to study the effects of exposure to heat, cardiovascular and hormonal responses were measured in 10 male cocaine addicts (after 4 weeks and 1 year of abstinence) and in 10 normal men. Subjects sat for 30 minutes in a sauna room. Hormonal (ACTH, beta endorphin, (beta EP) met enkephalin (met-enk), prolactin (PRL), cortisol) and cardiovascular parameters (heart rate, systolic and diastolic blood pressure) were measured before and after heat exposure. Basal levels of ACTH, beta EP, Met-Enk and cortisol were similar in normal and in cocaine addicts, whereas plasma PRL values were higher in drug abusers after long-term abstinence. All the examined hormones, with the exception of Met-Enk, were significantly raised in normal control subjects at the end of sauna. In contrast, no significant hormonal response to hyperthermia was observed in cocaine addicts either after 4 weeks and 1 year of abstinence. No changes were detected in heart rate and blood pressure in each group, indicating that the cardiovascular adaptive responses to hyperthermia in cocaine addicts was unaltered. The results of the present study provide evidence of an impairment of the hormonal response to hyperthermia in cocaine abusers. In conclusion, cocaine abuse produces alteration in the hypothalamic-pituitary function which persists after a long period of abstinence.