Chapter 7 - Cocaine and Neuromolecular Imaging of Neurotransmitters in the Brain: BRODERICK PROBE® Laurate Nanobiosensors in Mesocorticolimbic Neurons and the Nucleus Accumbens: Sex and Genes

Abstract

Cocaine is a psychostimulant and an addicting drug. Addiction is defined as the repetition of untoward behaviors regardless of consequence, albeit devastating such as loss of home, family, income, and loved ones. The term, “addiction,” remains elusive and indeed the neuropathology underlying the brain process in one who becomes addicted remains elusive as well. Nonetheless, addicting drugs, such as cocaine, are known to act on the reward centers of the brain, both in the humans and animals. Dopamine (DA) is a causative neurotransmitter in the addiction and reward process. Sex responses to cocaine are factors. As described in this chapter, data show that females are dramatically more sensitive to cocaine than males and the sensitivity is due to hormonal dysfunction as shown by exfoliate cytologyin correlation to data showing cocaine-induced changes in vaginal electrical resistance in ohms. Cocaine actually shifts the estrous cycle out of phase. Moreover, the phenomenon of “serotonin deficiency” in the genetic animal model of depression, the Fawn-Hooded animal, is shown here to affect the usually enhanced responses of DA and serotonin to cocaine; serotonin deficiency exhibits comorbidity with drug abuse. Neuromolecular imaging (NMI) uses miniature nanobiosensors, smaller than a human hair, that allow the selective electrochemical detection of neurotransmitters in vivo within seconds, online, and in real time. In these cocaine studies, BRODERICK PROBE® laurate nanobiosensors image signals within mesocorticolimbic neuronal terminals, the nucleus accumbens, while at the same time, infrared photobeams monitor open-field movement behaviors in the same subjects. Thus, NMI enables studies of cocaine's cause and effects. Finally, this real-time imaging of neurotransmitters is an advance toward personalized medicine since NMI video tracks, point by point, the individual effects of cocaine as each animal is studied as its own control.