INVOLVEMENT OF CENTRAL HISTAMINE IN THE EARLY PHASE OF ACTH AND CORTICOSTERONE RESPONSES TO ENDOTOXIN IN RATS

Citation
L. Givalois et al., INVOLVEMENT OF CENTRAL HISTAMINE IN THE EARLY PHASE OF ACTH AND CORTICOSTERONE RESPONSES TO ENDOTOXIN IN RATS, Neuroendocrinology, 63(3), 1996, pp. 219-226
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences,"Endocrynology & Metabolism
Journal title
ISSN journal
0028-3835
Volume
63
Issue
3
Year of publication
1996
Pages
219 - 226
Database
ISI
SICI code
0028-3835(1996)63:3<219:IOCHIT>2.0.ZU;2-R
Abstract
The involvement of histaminergic transmission in the rapid and sustain ed plasma ACTH and corticosterone (CORT) responses induced in consciou s rats by intra-arterial infusions of 25 mu g . kg(-1) Escherichia col i lipopolysaccharide (LPS) was investigated. LPS challenge produced a rapid and transient increase (+ 62%) in the amount of histamine (HA) i n the median eminence 15 min after LPS administration, which contraste d with constant concentrations of plasma HA throughout the entire stud y (up to 480 min). Blockade of histaminergic receptors by intra-arteri al pretreatment with H-1 or H-2 antagonists (mepyramine, 1 mg/rat, and cimetidine, 2 mg/rat), administered separately, did not affect either ACTH or CORT responses to LPS. Pretreatment with the same doses of th e two antagonists in combination very significantly but transiently im paired the earliest phase (30 min) of the ACTH and CORT responses, wit hout any apparent effect on the late phase of these responses. Pretrea tment of the animals with an H-3-receptor agonist (R alpha-methylhista mine dihydrochloride, 1 mg/rat) similarly blunted the early corticotro pic responses to LPS, and also slightly depressed the long-lasting COR T response. These findings support the view that activated central HA transmission may be a key intermediate mechanism triggering the CRH41- ACTH-CORT responses to LPS, in addition to the previously demonstrated activating role of catecholaminergic afferences to the CRH41 neurons during this early complex phase of corticotropic response to LPS.