[Is the baroreflex heart response to prostaglandin E1 less than that to nitroglycerin?]

The purpose of this study is to investigate and compare the reflex heart rate response to bolus injections of prostaglandin E1 (PGE1) and to nitroglycerin (NTG). One hundred and fifty seven patients under isoflurane nitrous oxide in oxygen anesthesia were studied prior to elective surgery. They were divided into following two groups: NTG group; n = 101 (male 54, female 47), 49.8 +/- 19.1 years of age, and PGE1 group; n = 56 (male 31, female 25), 54.7 +/- 15.3 years of age. The bolus injections of NTG and PGE1 produced a significant increase in heart rate as an indicator of arterial baroreflex response. However, there was no statistical difference between the two groups. Negative linear relationship between age and magnitude of reflex heart rate response to reduction of blood pressure (delta HR/delta SBP) was present in NTG group (r = -0.57, P < 0.01) and PGE1 group (r = -0.50, P < 0.01). These results suggest that the degree of the reflex heart rate response to bolus injection of NTG and PGE1 is almost identical in patients under isoflurane anesthesia.