Sex differences in the rodent hippocampal opioid system following stress and oxycodone associated learning processes
Autor: | Jasna Chalangal, Sanoara Mazid, Teresa A. Milner, Kyle A. Windisch |
---|---|
Rok vydání: | 2021 |
Předmět: |
Male
Enkephalin Clinical Biochemistry Conditioning Classical Receptors Opioid mu Toxicology Biochemistry κ-opioid receptor Hippocampus Article Behavioral Neuroscience Receptors Opioid delta Medicine Animals Learning Chronic stress Opioid peptide Biological Psychiatry Pharmacology Neurons Sex Characteristics business.industry Receptors Opioid kappa Opioid-Related Disorders Associative learning Rats Analgesics Opioid Microscopy Electron Opioid Opioid Peptides Receptors Estrogen Receptors Opioid Female μ-opioid receptor business Neuroscience Oxycodone Stress Psychological medicine.drug |
Zdroj: | Pharmacol Biochem Behav |
ISSN: | 1873-5177 |
Popis: | Over the past two decades, opioid abuse has risen especially among women. In both sexes hippocampal neural circuits involved in associative memory formation and encoding of motivational incentives are critically important in the transition from initial drug use to drug abuse/dependence. The opioid circuit particularly the mossy fiber pathway, are crucial for associative memory processes important for addiction. Our anatomical studies, especially those utilizing electron microscopic immunocytochemistry, have provided unique insight into sex differences in the distribution of opioid peptides and receptors in specific hippocampal circuits and how these distributions are altered following stress and oxycodone-associative learning processes. Here we review the hippocampal opioid system in rodents with respect to ovarian hormones effects and baseline sex differences then sex differences following acute and chronic stress. Next, we review sex differences in the hippocampal opioid system in unstressed and chronically stressed rats following oxycodone conditioned place preference. We show that opioid peptides and receptors are distributed within hippocampal circuits in females with elevated estrogen states in a manner that would enhance sensitivity to endogenous and exogenous opioids. Moreover, chronic stress primes the opioid system in females in a manner that would promote opioid-associative learning processes. In contrast, chronic stress has limited effects on the opioid system in males and reduces its capacity to support opioid-mediated learning processes. Interestingly, acute stress appears to prime males for opioid associative learning. On a broader scale the findings highlighted in this review have important implications in understanding sex differences in opioid drug use and abuse. |
Databáze: | OpenAIRE |
Externí odkaz: |