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| Authors | Brain regions | Models | Drugs | Measurements | Main results |
|
| Moradi et al. [64] | VTA | Acute pain | D1 antagonist SCH23390
D2 antagonist sulpiride | Tail-flick test | (i) Blockage of the D1 and D2 receptors had a similar effect, as inhibiting the antinociception induced by carbachol |
Taylor et al. [70]
Siahposht-Khachaki et al. [73]
Yazdi-Ravandi et al. [74]
Martikainen et al. [29] | NAc | Acute pain and neuropathic injury (SNI and CCI) | D1 antagonist SCH23390
D1 agonist SKF38393
D2 antagonist sulpiride
D2 agonist quinpirole | Formalin test
Tail-flick test | (i) Neuropathic injury decreased the mRNA levels of both D2 and D1 receptors
(ii) The blockade of D1- and D2-like receptors showed the similar pharmacological effects
(iii) The activation of the D2 receptors had more profound analgesic effects |
Sogabe et al. [84]
Granon et al. [92]
Fletcher et al. [91] | PFC | Acute pain
In vitro | The same as above | Electrophysiological recording
Attentional set-shifting task | (i) The D1 receptors tend to affect the cognitive aspect of pain, like via distraction
(ii) The D2 receptors may directly regulate the pain perception or nociceptive responses
(iii) The activation of the D2 receptors had more profound analgesic effects |
Magnusson and Fisher [98]
Ansah et al. [99]
Saunier-Rebori and Pazo [101] | Striatum | Inflammatory pain | D1 antagonist SCH23390
D1 agonist SKF38393
D2 antagonist eticlopride
D2 agonist quinpirole | Formalin test
Jaw opening reflex | (i) The activation of the D2 receptors had antihypersensitive effect, but not D1 receptors |
| Hagelberg et al. [103, 104] | Striatum | Clinical chronic orofacial pain | | PET | (i) Healthy male volunteers with a low D2 receptor, while D2 receptor availability of patients increased, which predicted a low synaptic DA concentration and a high capacity of recruiting pain inhibitory circuitry |
Ben-Haim et al. [109]
Li et al. [107]
Tobaldini et al. [114] | PAG | Acute pain | DA agonist apomorphine
D2 antagonist eticlopride
D1 antagonist SCH-23390
Opiate heroin and morphine | Hot plate test
Tail-flick test
Mechanical paw-withdrawal test | (i) The analgesic effect of apomorphine was blocked by D2 antagonist, but not by D1 antagonist
(ii) Blockage of the D1 and D2 receptors had a similar effect, as reducing the antinociception induced by the opioids
(iii) The activation of D1 receptors could enhance the opioid- and D2-induced antinociception |
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