Paraventricular nucleus histamine increases blood pressure by
adrenoreceptor stimulation of vasopressin release..
Bealer, Steven L., and Stanley O. Abell.
Department of Physiology and Biophysics, University of Tennessee,
Memphis, Memphis, TN 38163
APStracts 2:0034H, 1995.
The role of adrenoreceptor stimulation and the peripheral mechanism
mediating the increase in mean arterial blood pressure (MAP) and
heart rate (HR) during administration of histamine (HA) in the
paraventricular nucleus/anterior hypothalamic (PVN/AH) region was
evaluated in conscious rats. HA administered through microdialysis
probes in the PVN/AH region increased MAP (18 +/- 1 mmHg) and HR (81 +/-
10 bpm). The pressor response was abolished by simultaneous
administration of phentolamine (alpha-1 and alpha-2 antagonist) or
prazosin (alpha-1 antagonist), but not altered by yohimbine (alpha-2
antagonist). The tachycardia was not effected by any adrenergic
antagonist. Furthermore, ganglionic blockade did not reduce the
increase in MAP (21 +/- 2 mmHg) during PVN/AH perfusion with HA, while
V1-vasopressin receptor blockade abolished the pressor response (4 +/-
2 mmHg). These data suggest that HA administered to the PVN/AH
increases blood pressure by local release of norepinephrine and
alpha-1 adrenoreceptor stimulation of vasopressin secretion, while
the tachycardia is not mediated by alpha-adrenoreceptors.
Received 29 September 1994; accepted in final form 24 January
1995.
APS Manuscript Number H879-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 February 1995.