cardiovascular system
• homozygotes exhibit a significant 9% reduction in circulating blood volume, although total body weight, hematocrit values, and red blood cell counts remain normal
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• homozygotes display normal baseline heart rates relative to wild-type mice
• however, the bradycardiac response to electrical stimulation of the vagus nerve is significantly attenuated, indicating a CNS defect
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hypotension
(
J:110099
)
• under basal conditions, homozygotes exhibit significantly reduced systolic, diastolic and mean arterial pressures relative to wild-type mice
• however, no significant changes in heart rate, heart size and histology, blood chemistry, blood cell counts, cardiac output or renal function are observed
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• homozygotes show complete absence of AVP-induced vasopressor responses; instead, AVP causes a decrease in blood pressure, partly through V2 receptor-mediated release of nitric oxide from the vascular endothelium
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nervous system
• homozygotes display significantly impaired arterial baroreceptor reflexes
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homeostasis/metabolism
• homozygotes exhibit significantly reduced baseline atrial natriuretic peptide levels relative to wild-type mice
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• homozygotes display normal baseline corticosterone levels relative to wild-type mice
• responses to vasoactive hormones including AVP remain mostly intact; however, the ACTH-stimulated corticosterone response is significantly reduced
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endocrine/exocrine glands
• homozygotes show abnormal adrenal gland histology, with unclear adrenocortical zonation and enhanced depositions of lipofuscin in the reticular layer
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muscle
• homozygotes show complete absence of AVP-induced vasopressor responses; instead, AVP causes a decrease in blood pressure, partly through V2 receptor-mediated release of nitric oxide from the vascular endothelium
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behavior/neurological
• homozygotes display impaired spatial memory in an eight-arm radial maze task, with an increase in the number of errors after several days of training sessions compared to controls
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