Ritter S, Dinh TT, Pedrow C, Roellich K (2002) Immunotoxic lesion of catecholamine afferents to paraventricular hypothalamus (PVH) impairs the corticosterone response to glucoprivation but not the basal secretory rhythm or response to swim stress. Neuroscience 2002 Abstracts 865.4. Society for Neuroscience, Orlando, FL.
Summary: Catecholamine afferents from the hindbrain densely innervate the medial parvicellular part of the PVH, which contains CRH neurons critical for control of corticosterone (CORT) secretion. However, the precise role of these afferents in control of CORT secretion is unclear. Here the immunotoxin, saporin conjugated to anti-dopamine B-hydroxylase(DSAP), which selectively lesions norepinephrine and epinephrine neurons, or unconjugated saporin (SAP) control solution, was microinjected into the PVH. After extensive habituation to testing conditions, DSAP and SAP rats were injected with 2-deoxy-D-glucose (2DG, 250mg/kg) or vehicle or subjected to a 5-min forced swim. Blood was sampled remotely between 0 and 240 min for radioimmunoassay of CORT. In a third test, blood was sampled every 4 hr for 24 hr to assess the basal secretory rhythm of CORT. Subsequently, loss of dopamine B-hydroxylase containing terminals without destruction of CRH neurons in the PVH of DSAP rats was confirmed by immunohistochemistry. In DSAP rats, the CORT response to 2DG was reduced dramatically to 29% of the response in SAP controls. In contrast, DSAP and SAP rats did not differ in their basal secretory rhythm or their CORT response to swim stress, indicating for the first time a stimulus-specific role of catecholamine afferents in control of CORT secretion. This finding is complemented by other work in which we (with A.G. Watts and G. Sanchez-Watts) show that these catecholamine afferents are required for 2DG-induced CRH gene expression, but not basal expression.
Related Products: Anti-DBH-SAP (Cat. #IT-03)