ABSTRACT
Spontaneously hypertensive rats (SHRs) were compared to Wistar-Kyoto (WKY) and Wistar (WIS) rats on 18 behaviors to determine strain differences while undisturbed and when being restrained by a jacket and tether system often used for monitoring blood pressure chronically. Male SHRs unrestrained in the home cage initially exhibited greater magnitudes of body grooming, quadrant changes, turning, sniffing and rearing than WKYs, whose behavioral levels remained low throughout the entire session. SHRs and WISs gradually declined in behavioral levels within the sessions. The effects of restraint significantly decreased the exploratory/activity behaviors of nose poking, rearing and quadrant changes, with SHRs showing a greater decrement as a result of the restraint. Because of this differential effect of restraint on behaviors distinguishing SHRs and WKYs, studies simultaneously measuring behavior and blood pressure should be interpreted with caution, especially when comparing strains. The hypoactivity of the WKY would suggest the use of an additional control strain in behavioral studies.
Subject(s)
Behavior, Animal/physiology , Hypertension/physiopathology , Animals , Male , Rats , Rats, Inbred SHR , Rats, Inbred Strains , Rats, Inbred WKY , Restraint, PhysicalABSTRACT
The effect of intraventricular perfusion with hypertonic saline (HS) or angiotensin II (ANG II) on cerebrospinal fluid (CSF) vasopressin (AVP), blood pressure and heart rate was determined in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. There was a marked reduction in the central peptidergic response in the SHR. Pretreatment with the AVP (V1) antagonist abolished the pressor response to intraventricular HS in the WKY rats, but not in the SHR.
Subject(s)
Brain/metabolism , Hypertension/genetics , Rats, Inbred SHR/metabolism , Rats, Inbred Strains/metabolism , Angiotensin II/pharmacology , Animals , Arginine Vasopressin/cerebrospinal fluid , Blood Pressure , Heart Rate , Hypertension/metabolism , Male , Rats , Saline Solution, HypertonicABSTRACT
Intraventricular perfusion with a hypertonic sodium chloride solution elicits increases in cerebrospinal fluid vasopressin and blood pressure and a decrease in heart rate. The central peptide response was greatly reduced in the hypertensive rat. Central pretreatment with the vasopressin (V1) antagonist completely abolished the pressor response to hypertonic sodium chloride in the normotensive animal. Results suggest that a central vasopressin receptor may play a role in the control of blood pressure.
