Autonomic nervous system control of heart rate during baroreceptor activation in conscious and anesthetized XXXX .

@entity4485 @entity4774 @entity1854 @entity591 @entity551 @entity2647 @entity3897 @entity35 @entity9966 @entity2165 @entity1168
Heart rate and blood pressure were recorded in conscious, freely behaving @entity35 through a catheter in the tail artery during administration of @entity1854 or @entity2647 through a catheter in the jugular vein. The sympathetic and parasympathetic components were distinguished by treating the @entity35 with @entity2165 or @entity9966 . Reflex @entity1168 induced by all doses of @entity2647 was almost totally blocked blocked following @entity9966 treatment. Reflex @entity591 induced by small to moderate doses of @entity1854 was attenuated to an equal extent following @entity3897 or @entity2165 treatment. A similar experimental schedule was followed with a separate group of @entity35 to determine the effects of @entity4485 and @entity4774 anesthesia on the baroreceptor reflex. Both @entity4485 and @entity4774 equally attenuated the @entity591 response to a decrease in blood pressure. However, @entity4485 anesthesia resulted in a greater attenuation of the @entity1168 response to an increase in blood pressure than did @entity4774 anesthesia. These data support the conclusion that the parasympathetic nervous system is primarily responsible for baroreceptor reflex-induced @entity1168 in conscious @entity35 . The sympathetic and parasympathetic systems contribute equally to control baroreceptor reflex-induced @entity591 except in extreme acute @entity551 when the @entity591 is predominantly due to the activation of sympathetic nerves. The findings of the second experiment indicate that @entity4485 and @entity4774 affect sympathetic systems differently.
