Differential early time course activation of the brainstem catecholaminergic groups in response to various stresses.
The effects of various stressors (restraint, ether, histamine and insulin-induced hypoglycemia stress) on the early time course activation of the different catecholaminergic (CA) cell groups A1/C1, A2/C2 and locus ceruleus (LC) from the brainstem were studied. The activity of the central noradrenergic neurons was assessed by measuring in tissue punches the 3,4-dihydroxyphenylacetic acid (DOPAC) level, a side metabolite of noradrenaline (NA) and adrenaline biosynthesis that is thought to reflect the activity of NA cells. Short 5 min restraint stress led to an immediate increase of DOPAC level in the three CA groups. In the A1/C1 and A2/C2 groups the maximal increase, respectively +75 and +50%, was already reached at the end of the application of the stress while for the LC the maximum (+84%) was obtained 15 min after the onset of the stress. Return to baseline level was achieved within 2 h. Continuous immobilization stress did not further alter the DOPAC concentration in the LC and the A1/C1 while a progressive increase up to 85% in the A2/C2 group was seen over 20 min. Following a 2-min exposure to ether, DOPAC was increased in all three structures within 5 min. At this time the maximum was already reached in the A1/C1 and LC, respectively +99 and +43%. After histamine or insulin injection DOPAC level increased in the A1/C1 and A2/C2 in the +25/+50% range but was not significantly affected in the LC. In all the stress situations studied the increase in DOPAC level, particularly in the A1/C1 group always preceded or was concomitant to the increase of plasma corticosterone.(ABSTRACT TRUNCATED AT 250 WORDS)
Lachuer
J
J
INSERM U 171, CNRS URA 1195, Centre Hospitalier Lyon-Sud, Pierre Bénite, France.
Gaillet
S
S
Barbagli
B
B
Buda
M
M
Tappaz
M
M
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D002395:Catecholamines / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood; D004986:Ether; D006632:Histamine / Q000494:pharmacology; D007003:Hypoglycemia / Q000139:chemically induced / Q000150:complications; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008125:Locus Coeruleus / Q000503:physiopathology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000209:etiology / Q000503:physiopathology*
D002395:Catecholamines; D007328:Insulin; D004986:Ether; D015102:3,4-Dihydroxyphenylacetic Acid; D006632:Histamine; D003345:Corticosterone; D009638:Norepinephrine