[Response of the hypothalamo-corticotropic system to metyrapone in pigeons].
Chronic catheterization and miniature recording device allowed plasma corticosterone (B) and hypothalamic multiunit activity (MUA) to be simultaneously obtained from freely behaving, awake pigeons, before and for 4 hrs after intravenous injection of metyrapone. Injection of vehicle (tartric acid : 100 mg/4 ml/kg) led to MUA and B profiles quite similar to stress-induced responses, i.e., a rapid and sustained rebounding increase in hypothalamic firing rate and, shifted by 5-10 min, in plasma B. These responses were progressively attenuating for 90-120 mn. Metyrapone administration induced first a rapid and short MUA and B increase. Then both parameters drastically decreased near zero for about 2 hrs and were slowly restored to initial values within 3-4 hrs. It is suggested that metyrapone treatment inhibited both peripheral (B synthesis) and central (hypothalamic neurons) levels of the corticotropic axis.
D000302:Adrenal Cortex / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D010856:Columbidae / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D007031:Hypothalamus / Q000187:drug effects* / Q000502:physiology; D007700:Kinetics; D008797:Metyrapone / Q000494:pharmacology*
D003345:Corticosterone; D008797:Metyrapone
Etude de la réponse du système hypothalamo-corticotrope à la métopirone chez le pigeon.