Modes of adaptation of peripheral neuroendocrine mechanisms of the sympatho-adrenal system to short-term stress as studied in two inbred rat strains.
Alterations in mechanisms involved in catecholamine (CA) and corticosterone (B) regulation following short periods of stress have been investigated in two inbred rat strains: a strain more reactive to stress, Wistar-Kyoto (WK), and a less reactive strain, Brown-Norway (BN). Measurements after decapitation stress alone and after decapitation following different periods of immobilization stress, indicate that: (a) plasma CA levels immediately after severe stress (i.e. decapitation) are directly related to the behavioral reactivity of the two rat strains to stress but inversely related to adrenal gland size, their content of CA and biosynthetic enzymes, and to plasma levels of MHPG; (b) levels of B in adrenal glands and in plasma after stress are similar in both strains, in spite of different gland sizes; (c) CAT activity in presynaptic sympathetic terminals is directly related to plasma CA after short-term stress; and (d) liver COMT activity is directly related to plasma CA levels after stress, but inversely plasma levels of MHPG. The implications of the findings are discussed further in the text and lead to the conclusion that the BN strain represents a mode of a slower response to stressful stimuli than WK.
D000222:Adaptation, Physiological; D000311:Adrenal Glands / Q000503:physiopathology*; D000818:Animals; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism*; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D003345:Corticosterone / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D013045:Species Specificity; D013312:Stress, Physiological / Q000503:physiopathology*
D002395:Catecholamines; D002394:Catechol O-Methyltransferase; D002795:Choline O-Acetyltransferase; D003345:Corticosterone; D009638:Norepinephrine; D004837:Epinephrine