Related Experiment Video
Updated: Jun 21, 2026
12:20
Use of the Operant Orofacial Pain Assessment Device (OPAD) to Measure Changes in Nociceptive Behavior
Published on: June 10, 2013
Opiate effects on aversive midbrain stimulation in rats
1Department of Psychiatry, The University of Texas, Health Science Center at Dallas, Dallas, TX 75235, USA.
Neuroscience Letters
|July 17, 2009
Summary
Morphine effectively reduced aversive behavior in rats by blocking escape responses to midbrain stimulation. Naloxone, an opioid antagonist, reversed morphine
Area of Science:
- Neuroscience
- Behavioral Pharmacology
Background:
- Opioid receptors are involved in pain and reward pathways.
- Electrical stimulation of specific brain regions can elicit aversive responses.
Purpose of the Study:
- To investigate the effect of morphine on aversive behaviors induced by midbrain stimulation in rats.
- To determine if naloxone can block morphine's effects on these behaviors.
Main Methods:
- Rats were trained to press a bar to escape electrical stimulation in aversive midbrain sites.
- Morphine was administered to assess its effect on bar pressing behavior.
- Naloxone was administered alone and in combination with morphine.
Main Results:
- Morphine significantly decreased bar pressing behavior, indicating a reduction in escape responses.
- The aversive sites included the dorsal central gray area (DCG), ventral reticular formation (VRF), and lateral tegmentum (LT).
- Naloxone, without affecting behavior alone, blocked the anti-aversive effects of morphine at all tested sites.
Conclusions:
- Morphine exerts anti-aversive effects mediated by opioid receptors in specific midbrain regions.
- Naloxone's blockade of morphine's effects confirms the involvement of the opioid system in modulating aversive responses to midbrain stimulation.
Related Concept Videos
01:25Analgesia and Pain Management
Pain is critical to various clinical pathologies, provoking an urgent need for effective management. Pain, whether acute or chronic, is a complex neurochemical process. Its alleviation depends on the type, with nonopioid analgesics effective for mild to moderate pain, such as musculoskeletal or inflammatory pain, while neuropathic pain responds best to anticonvulsants, tricyclic antidepressants, or serotonin/norepinephrine reuptake inhibitors. For severe acute or chronic pain, opioids may be...
01:15Opioid Analgesics: Synthetic and Semisynthetic Opioids
Synthetic and semisynthetic opioids are pivotal in pain management and tackling opioid addiction. Semisynthetic opioids, including morphinans (morphine derivatives), oxycodone, oxymorphone, hydrocodone, and hydromorphone, have improved pharmacokinetic profiles compared to morphine. Additionally, heroin and 6-MAM (6-Monoacetylmorphine) show better CNS penetration than morphine due to heightened lipid solubility. Hydromorphone, a potent opioid, undergoes hepatic metabolism to form the active...