Patterns of hemodynamic responses associated with central activation of coronary vasoconstriction.
Previous studies in our laboratory have identified several central sites from which coronary vasoconstriction can be elicited by electrical stimulation. The present study was conducted to determine if specific patterns of hemodynamic responses are associated with activation of the coronary vasoconstrictor pathway in the hypothalamus, pons, and medulla. Cats anesthetized with chloralose were instrumented for recording arterial pressure, heart rate, and coronary, femoral, renal, and mesenteric blood flow velocities. After vagotomy and atenolol (1 mg/kg iv), anterior hypothalamus (AHA), parabrachial nucleus (PBN), a site very close to the ventral surface of the pons lateral to the pyramidal tract, and rostral ventrolateral medulla (RVLM) were stimulated electrically. Stimulation produced a decrease in coronary blood flow that was associated with all of the cardiovascular components of the defense reaction, an integrated response that included a decrease in hindquarter vascular resistance (blocked by methyl atropine), increases in renal and mesenteric vascular resistances, and a pressor response, except no change in renal vascular resistance from RVLM. Different patterns of hemodynamic responses were obtained from sites outside the coronary vasoconstrictor areas. From these results we conclude that coronary vasoconstriction is a frequent component of the defense reaction.
Jones
L F
LF
Department of Pharmacology, University of Iowa, Iowa City 52242.
Gutterman
D D
DD
Brody
M J
MJ
D000818:Animals; D007025:Anterior Hypothalamic Nucleus / Q000502:physiology*; D002415:Cats; D003326:Coronary Circulation / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D006439:Hemodynamics; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D011149:Pons / Q000502:physiology*; D014661:Vasoconstriction / Q000502:physiology*