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In vivo Infusion of Adrenaline Stimulates Corticotropin‐Releasing Hormone‐Producing Neurons when given Centrally but not Distally
Author(s) -
Barbanel Gérard,
Ixart Guy,
Assenmacher Ivan
Publication year - 1991
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.1991.tb00256.x
Subject(s) - median eminence , medicine , endocrinology , cannula , corticotropin releasing hormone , perfusion , hormone , hypothalamus , epinephrine , basal (medicine) , chemistry , surgery , insulin
There is evidence that adrenaline stimulates the release of corticotropin‐releasing hormone (CRH‐41) from hypothalamic neurons. This study was carried out to ascertain the effects of adrenaline on the perikarya and/or distal terminals of these cells. All experiments were performed on unrestrained rats having chronic intracerebroventricular cannulas in the lateral ventricle or intracerebral cannulas in the paraventricular nucleus and, additionally, a push‐pull median eminence cannula. Adrenaline (1.4 μg adrenaline bitartrate in 5 μI vehicle for intracerebroventricular infusion, or 0.7 μg in 0.25 μI for intracerebral infusion) was infused over 2 min, and 15‐min median eminence perfusate samples were collected over 2 to 3 h. In another experiment the median eminence was directly perfused for 30 min with a total of 1.2 μg (n = 4) or 12 μg (n = 3) adrenaline per rat. Intracerebroventricular or intracerebral adrenaline induced a swift, short‐lived (15 min) CRH‐41 surge which reached 7 to 10 times the basal level. Direct perfusion of the median eminence with adrenaline (around the nerve endings of CRH‐41‐producing neurons) did not stimulate CRH‐41 release and higher amine concentrations even tended to depress the neuropeptide release. The stimulatory effect of adrenaline on the corticotropic axis appears, therefore, to be restricted to the central dendro‐perikaryal region of CRH‐41‐producing neurons.