The capsaicin sensitivity of the preoptic region is preserved in adult rats pretreated as neonates, but lost in rats, pretreated as adults

M. Hajós, F. Obál, G. Jancsó, F. Obál

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

1. Two days old rats were pretreated with subcutaneous injection of 50 mg/kg, and adult animals with either 20, 50 or 300 mg/kg capsaicin. The responsiveness of these and naive animals to microinjection into the preoptic region of capsaicin (10 μg) and to subcutaneously injected capsaicin (2 mg/kg) was studied at the age of 3-4 months by recording the tail skin vasodilatation and colon temperature, respectively. 2. On preoptic injection of capsaicin, the reaction of neonatally-pretreated adult rats was similar to that of naive animals, while in all groups pretreated as adults the tail skin vasodilatation was abolished. 3. In response to 2 mg/kg capsaicin administered subcutaneously, the group pretreated neonatally and the adults pretreated with 20 mg/kg capsaicin produced significantly less hypothermia than the naive animals. Rats pretreated as adults with 50 and 300 mg/kg capsaicin failed to show a hypothermic reaction. 4. It is concluded that the sensitivity of the preoptic region to capsaicin is preserved when 2 days old rats are treated with the drug, but lost when adults are injected with capsaicin. These features of capsaicin sensitivity indicate a functioning preoptic and an impaired extrapreoptic thermoregulation in rats pretreated with capsaicin as neonates.

Original languageEnglish
Pages (from-to)219-222
Number of pages4
JournalNaunyn-Schmiedeberg's Archives of Pharmacology
Volume324
Issue number3
DOIs
Publication statusPublished - Nov 1 1983

Keywords

  • Capsaicin
  • Neonate rat
  • Preoptic region
  • Thermoregulation

ASJC Scopus subject areas

  • Pharmacology

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