Stimulation of catecholaminergic neurons in the ventral medulla by various stressors monitored with in vivo electrochemistry.
Catecholaminergic metabolism in the A1 cell group of the ventrolateral medulla oblongata was followed after application of 3 interoceptive stressful stimuli by monitoring the extracellular concentration of 3,4-dihydroxyphenylacetic acid (DOPAC) with an in vivo voltammetric approach. These stimuli provoked an increase of the DOPAC signal with different time course and amplitude. Histamine led to a maximal 200% increase that vanished within two hours. Insulin induced a long-lasting increase of up to 350% that could be reversed by glucose infusion. Electrical stimulation of the sciatic nerve triggered an immediate increase of up to 140% which stopped with the ending of the stimulation. The time-course of this activation is compatible with a possible involvement of catecholaminergic afferents from the A1 group projecting to the paraventricular nucleus in the stimulation of the hypothalamic neurosecretory cells elicited by the stressors.
Rehorek
A
A
INSERM U 171/CNRS URA 1195, Centre Hospitalier Lyon Sud, Pierre Benite, France.
Lachuer
J
J
Brun
P
P
Gonon
F
F
Tappaz
M
M
D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D004558:Electric Stimulation; D004563:Electrochemistry / Q000379:methods; D006632:Histamine / Q000494:pharmacology; D007003:Hypoglycemia / Q000503:physiopathology; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D012584:Sciatic Nerve / Q000502:physiology*; D012965:Sodium Chloride / Q000494:pharmacology
D007328:Insulin; D015102:3,4-Dihydroxyphenylacetic Acid; D012965:Sodium Chloride; D006632:Histamine