DEVELOPMENT OF WATER-IMMERSION PRODUCED ANALGESIA

Nociceptive and antinociceptive systems change dramatically during the first 10 days of life in rats. The present studies sought to determin e whether exposure to water stress can produce analgesia during this p eriod, and when in the ontogeny changes in magnitude and duration of s uch stress-induced analgesia occur. It was found that exposure to wate r reliably induced analgesia as early as 3 days postnatally. This anal gesia increased in magnitude and duration at the age of 17-20 days, wh en supra-spinal descending inhibition develops, and depended on the te mperature of the water and duration of exposure. (C) 1995 John Wiley a nd Sons, Inc.