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Characterization of the Cardiovascular Responses to Intrathecal Administration of Angiotensin II (Ang II) in Conscious Rats
Author(s) -
Veitenheimer Britta,
Osborn John
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.792.3
Subject(s) - angiotensin ii , medicine , spinal cord , angiotensin ii receptor type 1 , receptor , endocrinology , heart rate , intrathecal , blood pressure , pharmacology , chemistry , anesthesia , psychiatry
Currently, little is known about spinal neurotransmitters and receptors regulating sympathetic nerve activity (SNA) and therefore arterial pressure (AP) in conscious animals. Ang II is important in brain pathways regulating AP, but little is known about its role at the level of the spinal cord. Previous studies have reported AT1 receptors in the intermediolateral cell column (IML), the location of sympathetic preganglionic cell bodies. In addition, Ang II has been found in many neurons in the PVN ‐ a brain region that projects to the IML. However, to our knowledge, the AP and heart rate (HR) responses to intrathecally (i.t.) administered Ang II in conscious rats has not been reported. The present study was conducted to measure the AP and HR responses to several doses of i.t. administered AngII in conscious rats. At least 5 days prior to experiments, male Sprague Dawely rats were instrumented for telemetric measurement of AP and i.t. administration of three doses of Ang II: 1μg, 10μg and 100μg. Peak increases in AP occurred within ~4 minutes, reaching levels of 12 + 3, 22 + 5, and 56 + 5 mm Hg respectively. Corresponding changes in HR were 38 + 15, 17 + 30, and ‐27 + 20 BPM. These data support the hypothesis that i.t. Ang II increases AP in conscious rats and suggest a possible role for spinally released Ang II in the regulation of SNA and AP in conscious rats. Supported by NIH Grant HL064178.