Abstract
We investigated 8 healthy male volunteers, evaluating RII and RIII thresholds every 6 h starting from noon, for a 24-h period. Both reflex responses exhibited a circadian rhythmicity: the lowest values were found in the early morning (9.1 ± 3.0 and 13.1 ± 4.4 mA, respectively), while the highest values were observed at midnight (13.1 ± 3.5 and 18.5 ± 5.3 mA). Also mean cosinor analysis indicated the existence of a significant rhythm with acrophase at 20:12 for RII and 22:29 for RIII. In 4 subjects, β-endorphin plasma (β-EP) level was tested during the day. No correlation was observed between circadian changes of β-EP and RIII threshold. Other factors are likely to be involved in the circadian variation of nociceptive flexion reflex in man.
Original language | English |
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Pages (from-to) | 403-410 |
Number of pages | 8 |
Journal | Pain |
Volume | 25 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1986 |
ASJC Scopus subject areas
- Clinical Neurology
- Psychiatry and Mental health
- Neuroscience(all)
- Neurology
- Pharmacology
- Clinical Psychology