SEX DIFFERENCES AND ADDICTION: PRECLINICAL STUDIES OF NEURAL MECHANISMS AND DEVELOPMENTAL INFLUENCES
Jill B Becker
Biopsychology Area Chair, Patricia Y. Gurin Collegiate Professor of Psychology
Research Professor Molecular & Behavioral Neuroscience Institute
University of Michigan, Ann Arbor, MI USA
The choices that males and females make to survive and reproduce successfully have been shaped by evolutionary forces in different ways. Furthermore, environmental influences interact with biological sex differences during development, and in the adult, to produce and sometimes exacerbate sex differences in the brain. In the female rat, estradiol decreases food intake and the motivation for food while enhancing motivation for a mate as well as drugs of abuse. Sex differences in the motivation to take drugs of abuse and the escalation of drug taking behavior are seen for all classes of abused drugs in humans and rodents.
We find that in females, but not males, there are rapid effects of estradiol on the ascending dopamine system that enhance the female’s motivation to engage in these behaviors. Female rats exhibit greater behavioral sensitization to cocaine, acquire cocaine self-administration more rapidly, and work harder to receive cocaine than males, and estradiol enhances these sex differences. The neural mechanisms mediating sex differences in the effect of estradiol on motivation are determined by hormonal exposure neonatally and during puberty, in the female rat. Using the rat as an animal model, we find that in females there are rapid effects of estradiol on the ascending dopamine system that enhance the female’s motivation to engage in these behaviors. Female rats exhibit greater behavioral sensitization to cocaine, acquire cocaine self-administration more rapidly, and work harder to receive cocaine than males, and estradiol enhances these sex differences. Developmentally, gestational stress alters drug taking behavior for both male and female rats, but in different ways.
Understanding the neural bases for sex differences in motivation and the ways that males and females differ are important for our understanding of the variety of mechanisms involved in the neural changes associated with sex differences in motivation and addiction. These ideas will be discussed within the larger context of sex differences in addiction.
Jill B Becker
Biopsychology Area Chair, Patricia Y. Gurin Collegiate Professor of Psychology
Research Professor Molecular & Behavioral Neuroscience Institute
University of Michigan, Ann Arbor, MI USA
The choices that males and females make to survive and reproduce successfully have been shaped by evolutionary forces in different ways. Furthermore, environmental influences interact with biological sex differences during development, and in the adult, to produce and sometimes exacerbate sex differences in the brain. In the female rat, estradiol decreases food intake and the motivation for food while enhancing motivation for a mate as well as drugs of abuse. Sex differences in the motivation to take drugs of abuse and the escalation of drug taking behavior are seen for all classes of abused drugs in humans and rodents.
We find that in females, but not males, there are rapid effects of estradiol on the ascending dopamine system that enhance the female’s motivation to engage in these behaviors. Female rats exhibit greater behavioral sensitization to cocaine, acquire cocaine self-administration more rapidly, and work harder to receive cocaine than males, and estradiol enhances these sex differences. The neural mechanisms mediating sex differences in the effect of estradiol on motivation are determined by hormonal exposure neonatally and during puberty, in the female rat. Using the rat as an animal model, we find that in females there are rapid effects of estradiol on the ascending dopamine system that enhance the female’s motivation to engage in these behaviors. Female rats exhibit greater behavioral sensitization to cocaine, acquire cocaine self-administration more rapidly, and work harder to receive cocaine than males, and estradiol enhances these sex differences. Developmentally, gestational stress alters drug taking behavior for both male and female rats, but in different ways.
Understanding the neural bases for sex differences in motivation and the ways that males and females differ are important for our understanding of the variety of mechanisms involved in the neural changes associated with sex differences in motivation and addiction. These ideas will be discussed within the larger context of sex differences in addiction.