Lateral hypothalamus: Site involved in pain modulation

• Published in: Neuroscience 1996, Vol.70 (2), p.449-460
• Main Authors: Dafny, N., Dong, W.Q., Prieto-Gomez, C., Reyes-Vazquez, C., Stanford, J., Qiao, J.T.
• Format: Article
• Language: English
• Subjects: analgesia; Animals; Biological and medical sciences; Dose-Response Relationship, Drug; Electric Stimulation; electrical stimulation; Fundamental and applied biological sciences. Psychology; Hypothalamus - physiology; Lateral hypothalamus; Male; Morphine - therapeutic use; noxious; Pain - drug therapy; Pain - physiopathology; pain center; Pain Measurement; Rats; Reaction Time - physiology; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/0306-4522(95)00358-4

The present study is an attempt to examine the neuronal circuitry of a supraspinal site engaged in pain modulation. Five physiological measures were postulated as the criteria for defining a central nervous system site engaged in the circuitry of pain modulation. The lateral hypothalamus met these five measures: (i) 81% of the lateral hypothalamus neurons (247/304) responded to noxious stimuli using a single cell recording procedure; (ii) stimulation of the periaqueductal gray-dorsal raphe area or the habenula modulated 98% and 87% of the lateral hypothalamus noxious-evoked activity; (iii) microiontophoretically applied morphine modulated 77% of the lateral hypothalamus noxious evoked activity; (iv) electrical stimulation of the lateral hypothalamus produced behavioral analgesia proportional to the stimulus integrity as assessed by the tail flick assay; and (v) morphine application into the lateral hypothalamus produced behavioral analgesia in a dose-response manner using the tail flick assay. In conclusion, the lateral hypothalamus can be considered one of the pain modulation sites.