The Opioids

 

Narcotic Analgesics

The opium poppy has a long history of use

Minor differences in molecular structure determine behavioral effects

Bioavailability predicts both physiological and behavioral effects

Opioids have their most important effects on the CNS and on the gastrointestinal tract

Box 11.1 Clinical Applications Saving a Life: Naloxone for Opioid Overdoses

Opioid Receptors and Endogenous Neuropeptides

Receptor binding studies identified and localized opioid receptors

Four opioid receptor subtypes exist

Several families of naturally occurring opioid peptides bind to these receptors

Box 11.2 The Cutting Edge Science in Action

Opioid receptor–mediated cellular changes are inhibitory

Opioids and Pain

The two components of pain have distinct features

Opioids inhibit pain transmission at spinal and supraspinal levels

Other forms of pain control depend on opioids

Opioid Reinforcement, Tolerance, and Dependence

Animal testing shows significant reinforcing properties

Dopaminergic and nondopaminergic components contribute to opioid reinforcement

Long-term opioid use produces tolerance, sensitization, and dependence

Box 11.3 Of Special Interest The Opioid Epidemic

Several brain areas contribute to the opioid abstinence syndrome

Neurobiological adaptation and rebound constitute tolerance and withdrawal

Environmental cues have a role in tolerance, drug abuse, and relapse

Treatment Programs for Opioid Use Disorder

Detoxification is the first step in the therapeutic process

Treatment goals and programs rely on pharmacological support and counseling