Hypothalamic neuropeptide release after experimental subarachnoid hemorrhage: in vivo microdialysis study.
OBJECTIVE
As evidence exists about independent regulation of peripheral and central release of the vasoactive and natriuretic neuropeptides arginine-vasopressin (AVP) and oxytocin (OXT), we investigated their release patterns following subarachnoid hemorrhage (SAH).


METHODS
After injection of 0.1 ml arterial blood or saline into the great cistern of 33 Wistar rats, AVP and OXT levels were measured in blood and by microdialysis in the hypothalamic supraoptic (SON) and paraventricular nucleus (PVN). For statistical analysis, the analysis of variance (ANOVA) was used with Tukey HSD post hoc ANOVA tests to determine specific group differences.


RESULTS
Plasma AVP and OXT peaked 2 h after SAH (P < 0.05), and normalized at 4 h. In the SON, both AVP and OXT peaked 4 h after SAH (P < 0.05). In the PVN, AVP increased in both groups (P < 0.05), while no OXT release occurred. By the sham group, any effect of experimental procedure was excluded.


CONCLUSIONS
The SAH-specific central neuropeptide release, which exceeded peripheral release and continued longer, may contribute to pathophysiological events following SAH.
Kleindienst
A
A
Neurosurgical Department, University of Greifswald, Greifswald, Germany. akleindienst@vcu.edu
Hildebrandt
G
G
Kroemer
S A
SA
Franke
G
G
Gaab
M R
MR
Landgraf
R
R
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D007031:Hypothalamus / Q000473:pathology*; D008297:Male; D009479:Neuropeptides / Q000378:metabolism*; D010121:Oxytocin / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013345:Subarachnoid Hemorrhage / Q000473:pathology*; D013495:Supraoptic Nucleus / Q000473:pathology
D009479:Neuropeptides; D001127:Arginine Vasopressin; D010121:Oxytocin