Conditioned saccharin avoidance induced by infusion of amphetamine in the nucleus accumbens shell and morphine in the ventral tegmental area: behavioral and biochemical study

A 40-year analysis of central neuroanatomical and neurochemical circuits mediating homeostatic intake and hedonic intake and preferences in rodents

This perspective review was written in response to the celebration of the 60th anniversary of the journal, Brain Research, and covers the evolving focus of my laboratory's work over 40 years in the neurobiological substrates of ingestive behavior in rodents. Following our initial work examining the effects of systemic and ventricular administration of general and selective opioid receptor agonists and antagonists on food intake under spontaneous, deprivation, glucoprivic and hedonic conditions, my laboratory in close collaboration with Drs. Gavril Pasternak and Ying-Xian Pan utilized an antisense oligodoxynucleotide knock-down technique affecting MOR-1, DOR-1, KOR-1 and ORL-1 genes as well as against G-protein subunits to study receptor mediation of opioid receptor agonist-induced feeding as well as feeding following regulatory challenges. Our laboratory employed intracerebral microinjection techniques to map limbic nucleus accumbens and ventral tegmental area central brain circuits mediating homeostatic and hedonic feeding responses through the use of selective mu, delta1, delta2 and kappa opioid receptor subtype agonists in combination with general and selective opioid, dopamineric, glutamatergic and GABAergic antagonists administered into the same site or the reciprocal site, allowing for the identification of a distributed brain network mediating these ingestive effects. Our laboratory in close collaboration with Dr. Anthony Sclafani then focused on the pharmacological, neuroanatomical and learning mechanisms related to the development of sugar- (sucrose, glucose and fructose) and fat- (corn oil) conditioned flavor preferences (CFP) in rats, and on murine genetic variance in food intake, preferences and the process of appetition.

NMDA-induced lesions of the nucleus accumbens core increase the innately rewarding saccharin solution intake and methamphetamine-induced conditioned place preference but not conditioned taste aversion in rats

The role of the nucleus accumbens (NAc) core in determining the valence of innately rewarding saccharin solution intake, methamphetamine (MAMPH)-induced conditioned taste aversion (CTA), and conditioned place preference (CPP) reward remains unclear. The present study utilized the "pre- and post-association" experimental paradigm (2010) to test whether the rewarding and aversive properties of MAMPH can be modulated by an N-methyl-D-aspartic acid (NMDA) lesion in the NAc core. Moreover, it tested how an NAc core NMDA lesion affected the innate reward of saccharin solution intake. The results demonstrate that MAMPH could simultaneously induce an aversive CTA and a rewarding CPP effect, supporting the paradoxical effect hypothesis of abused drugs, in particular amphetamine. Meanwhile, the NMDA-lesioned NAc core increased the reward effect of CPP but did not alter the aversive CTA effect. The NAc core NMDA lesion also enhanced the innate reward of saccharin solution intake. The NAc core therefore seemingly plays an inhibitory role in the innate reward of saccharin solution intake and in the CPP effect. The paradoxical effect hypothesis of abused drugs provides some explanations for the present data in the case of MAMPH administrations. The NAc core may play an essential role in modulating the rewarding but not the aversive properties of MAMPH. The present findings could contribute to the understanding and eventual advancement of clinical interventions for drug addiction and the development of novel pharmacological treatments.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Endogenous opioids and feeding behavior: A decade of further progress (2004-2014). A Festschrift to Dr. Abba Kastin

Functional elucidation of the endogenous opioid system temporally paralleled the creation and growth of the journal, Peptides, under the leadership of its founding editor, Dr. Abba Kastin. He was prescient in publishing annual and uninterrupted reviews on Endogenous Opiates and Behavior that served as a microcosm for the journal under his stewardship. This author published a 2004 review, "Endogenous opioids and feeding behavior: a thirty-year historical perspective", summarizing research in this field between 1974 and 2003. The present review "closes the circle" by reviewing the last 10 years (2004-2014) of research examining the role of endogenous opioids and feeding behavior. The review summarizes effects upon ingestive behavior following administration of opioid receptor agonists, in opioid receptor knockout animals, following administration of general opioid receptor antagonists, following administration of selective mu, delta, kappa and ORL-1 receptor antagonists, and evaluating opioid peptide and opioid receptor changes in different food intake models.