Pituitary-adrenal and adrenomedullary responses to noise in awake dogs.
Experiments characterized the dynamics of the pituitary and adrenocortical response to noise in awake dogs to determine if a dissociation exists between changes in plasma bioactive (bio) adrenocorticotropic hormone (ACTH) and immunoreactive (ir) ACTH. In addition, experiments determined the temporal relationship between cardiovascular, adrenomedullary, and adrenocortical responses induced by the acute presentation of noise. Trained dogs were prepared chronically with adrenal venous and femoral arterial cannulas. Experiments were done 48-96 h postsurgery and consisted of presentation of noise (75 dB; 0.25-8 kHz) for 3 min (n = 6) or of blood sampling alone (n = 5). In response to noise, mean arterial pressure and heart rate increased at 30 s and returned to base line at 4 min. Adrenal secretion of epinephrine and norepinephrine increased at 1 min and remained elevated until 4 min. Adrenal blood flow increased from 2 to 4 min as the result of a parallel increase in adrenal vascular conductance. Plasma bioACTH increased from 6 to 15 min in parallel with that of plasma irACTH. Before noise, the ratio of bioACTH to irACTH was 0.2-0.3, but the absolute change in bioACTH and irACTH after noise was not different. The increase in plasma ACTH occurred concomitant with or preceded an increase in cortisol secretion. Blood sampling alone caused no change in any variable. These data show that unexpected noise evokes a sequence of responses with rapid onset that includes tachycardia, hypertension, and increases in adrenomedullary secretion and adrenal vascular conductance.(ABSTRACT TRUNCATED AT 250 WORDS)
Engeland
W C
WC
Department of Surgery, Brown University, Rhode Island Hospital, Providence 02903.
Miller
P
P
Gann
D S
DS
D000313:Adrenal Medulla / Q000502:physiology*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D001522:Behavior, Animal; D004285:Dogs; D004837:Epinephrine / Q000378:metabolism; D006854:Hydrocortisone / Q000378:metabolism; D009622:Noise; D009638:Norepinephrine / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000502:physiology*; D014851:Wakefulness
D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine