Persistent pain responses under inflammation and corticosterone levels in juvenile rats born to adrenalectomized dams
Butkevich, I.P.; Mikhaĭlenko, V.A.; Bagaeva, T.R.; Makukhina, G.V.
Rossiiskii Fiziologicheskii Zhurnal Imeni I.M. Sechenova 94(3): 312-317
2008
ISSN/ISBN: 0869-8139 PMID: 18507160 Document Number: 624402
Juvenile Wistar rats born to dams adrenalectomized 34 weeks before mating were used to study the intensity of indices of behavioural pain responses (number of flexing + shaking and duration of licking patterns) produced by inflammation in the formation test as well as plasma corticosterone levels during the pain response. It has been found that dams' adrenalectomy does not change either basal corticosterone levels or the indices of pain response intensity. During persistent pain (25 min after the formation injection), corticosterone levels were enhanced reliably (p < 0.05) in offspring of both intact and adrenalectomized dams. Females born to adrenalectomized dams showed the higher corticosterone levels (p = 0.008) as a response to persistent pain as compared to those born to sham-operated dams. No differences in pain indices in female offspring of adrenalectomized and sham dams were revealed. There were no sex differences in the indices of pain response and corticosterone. Thus, the pain evoked by inflammation in the formalin test has an activating effect on the hypothalamo-hypophyseal-adrenocortical system in 25-day-old pups, but the released corticosterone fails to reduce pain intensity in the formalin test as evidenced by data obtained in offspring of adrenalectomized dams.