Endorphinergic modulation of neural reward systems indicated by behavioral changes

Dum, Jane; Herz, A.

doi:10.1016/0091-3057(84)90224-7

Cited by 85 publications

(41 citation statements)

References 23 publications

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“…Food consumption raises escape thresholds for noxious stimuli, and noxious stimuli will interrupt feeding. 28,29 Furthermore, as discussed above, 11 animals that expect a highly palatable food reward in a specific context have significantly higher pain thresholds when they are in that context. Importantly, their ability to wait for the expected reward was blocked by the opioid antagonist naloxone.…”

Section: Mesolimbic Dopamine Pathways and The "Decision Circuit"mentioning

confidence: 88%

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Understanding How Opioids Contribute to Reward and Analgesia

Fields¹

2007

Regional Anesthesia and Pain Medicine

103

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Opioids acting at the mu opioid (MOP) receptor produce powerful analgesia. They also produce an intensely rewarding effect that can lead to addiction. The analgesic effect of MOP receptor agonists derives from a direct inhibitory effect on pain transmission at the spinal-cord level and through activation of a descending pain-modulatory pathway. The rewarding effect of MOP agonists is the result of their actions in the mesostriatal dopamine pathway classically associated with both natural and drug rewards. Both the analgesic and rewarding effect of MOP agonists are best understood in the context of decision making under conditions of conflict. Pain is one of many competing motivational states, and endogenous opioids suppress responses to noxious stimuli in the presence of conflicting motivations, such as hunger or a threatening predator. When a food reward is available, MOP agonists microinjected into the mesostriatal circuit promote its consumption, while concomitantly suppressing responses to noxious stimulation. The mesostriatal "reward" circuit, thus, appears to perform a function critical to decision making and can either amplify or suppress responses to noxious stimuli.

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Section: Mesolimbic Dopamine Pathways and The "Decision Circuit"mentioning

confidence: 88%

“…9,10 Pain responses are also suppressed in situations in which rodents anticipate reward. 11 Under many circumstances, such suppression of pain responses can be prevented by administration of nonselective opioid-receptor antagonists such as naloxone. Interestingly, in this regard, placebo analgesia can also be reversed by naloxone.…”

mentioning

confidence: 99%

Understanding How Opioids Contribute to Reward and Analgesia

Fields¹

2007

Regional Anesthesia and Pain Medicine

103

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“…Reward-associate cues also engage pain relief circuits. For example, a study with rats found that their withdrawal threshold to a painful stimulus was increased in an environment where they previously received a palatable food reward, an effect that was reversed with systemic administration of naloxone (Dum and Herz, 1984). Perhaps the reward responses the PAG neurons displayed in the current study are not responding to rewarding stimuli per se , but instead the neurons are activated in order to engage the descending pain modulatory circuit to favor approach behaviors to appetitive stimuli, especially in such cases that an animal is experiencing minor noxious stimuli.…”

Section: Discussionmentioning

confidence: 99%

“…This essential process is mediated by a complex circuitry that engages multiple regions of the brain such as prefrontal cortex, hypothalamus, hippocampus, ventral tegmental area, basal ganglia structures and more (Kelley et al, 2005). Indeed, it has been documented that expectancy of a food reward can activate endogenous opioid-mediated analgesia which is thought to be mediated by the PAG (Dum and Herz, 1984; Fields, 2004) and it is hypothesized that reward expectation elicits an analgesic response to allow an animal to ignore noxious stimuli and attend to a rewarding stimulus (Fields, 2007; Leknes and Tracey, 2008). …”

Section: Introductionmentioning

confidence: 99%

A Novel Role for the Periaqueductal Gray in Consummatory Behavior

Tryon

Mizumori

2018

Front. Behav. Neurosci.

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The periaqueductal gray (PAG) has a well-established role in pain processing, autonomic function and behavioral responses to fear. Anatomical work suggests the PAG may mediate food intake and reward processing as it has extensive reciprocal connections within brain circuits that mediate appetitive processes and consummatory behaviors such as prefrontal cortex, hypothalamus, amygdala, parabrachial nucleus (PBN) and ventral tegmental area (Kelley et al., 2005). Therefore, we investigated if the PAG of hungry rats has a functional role in appetitive and consummatory behaviors. To address this, PAG was pharmacologically inactivated during a spatial working memory task with muscimol (0.1–0.3 μg), a GABAA agonist via intracranial infusion. Inactivation of PAG led to reduced intake of food rewards and increased errors on this task. To focus on the specific effects PAG inactivation had on food consumption, PAG was inactivated during two separate food intake tasks in a separate group of rats. Again, PAG inactivation resulted in a significant decrease in food consumption, as well as an increased latency to consume food. We next investigated PAG neural responses to reward encounters. A different group of rats performed the same task used in Experiment 1 while the in vivo activity of PAG neurons was recorded. In a subset of PAG neurons, reward encounters elicited phasic excitation. A separate subset of PAG neurons were inhibited during reward encounters. These responses scaled with the size of the reward, with sustained excitation or inhibition in response to large rewards compared to small. Our data also show that separate groups of PAG neurons in awake behaving animals display either increased and decreased neural responses to reward encounters. Additionally, a proportion of neurons were modulated by the animals’ velocity. This study is the first to show that PAG neurons process reward-related information, perhaps to mediate consummatory behaviors related to food consumption.

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“…It has been shown that paraventricular GAL injection causes a significant increase in plasma noradrenaline (NA) levels (27), and that noradrenergic neurons play a role in appetite and ingestion responses to glucoprivation (11). Furthermore, sweets have been shown to stimulate the endogenous opioid system both by inducing a release of β-endorphin and by increasing the binding affinity of opioids at receptor sites (28,29). The differences in macronutrient preferences may indicate variation in responses such as these to carbohydrate availability.…”

Section: Discussionmentioning

confidence: 99%

Serotonergic regulation of galanin-induced selective macronutrient intake in self-selecting rats

Tanaka

Kido

2008

J. Med. Invest.

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: We investigated macronutrient intake after intraventricular injection of galanin (GAL, 3 nmol/5 μl/rat) and/or serotonin (5-HT, 50 nmol/5 μl/rat) in self-selecting fasted rats with preferences for either carbohydrates or fats. GAL injection significantly increased carbohydrate and total intake in all rats irrespective of macronutrient preference, whereas 5-HT alone did not affect macronutrient intake. The GAL-induced increase in total intake decreased to the level of saline controls when GAL was coinjected with 5-HT. The ratio of kilocalories of carbohydrates, fats and proteins (macronutrient energy ratio) after injections of GAL and/or 5-HT was similar to the saline control. In carbohydrate-preferring rats, GAL increased carbohydrate, protein and fat intake as well as total intake. Coinjection of GAL and 5-HT tended to decrease carbohydrate intake, but increase protein and fat intake. The macronutrient energy ratio after injection of GAL did not change, but the carbohydrate energy ratio decreased after 5-HT was injected, with or without GAL. In contrast, in fat-preferring rats, GAL significantly increased carbohydrate intake. Injection of 5-HT with or without GAL did not change total macronutrient intake. The macronutrient energy ratio did not change after GAL injection with or without 5-HT. These differences suggest that macronutrient preferences should be considered in any macronutrient intake study, and that serotonergic neurons play a part in the regulation of GAL-induced macronutrient intake.

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Endorphinergic modulation of neural reward systems indicated by behavioral changes

Cited by 85 publications

References 23 publications

Understanding How Opioids Contribute to Reward and Analgesia

Understanding How Opioids Contribute to Reward and Analgesia

A Novel Role for the Periaqueductal Gray in Consummatory Behavior

Serotonergic regulation of galanin-induced selective macronutrient intake in self-selecting rats

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