Attenuated cardiovascular effects of @entity4770 and XXXX in cold acclimated American bullfrogs, Rana catesbeiana.

@entity7784 @entity844 @entity101 @entity1426 @entity2918 @entity4770 @entity3774 @entity3352 @entity551
American bullfrogs, Rana catesbeiana respond to @entity2918 with changes in heart rate and blood pressure. These studies compare responses of warm (22 degrees C) and cold acclimated (5 degrees C) bullfrogs to @entity2918 . Gas chromatographic analysis determined equivalent @entity844 profiles in total lipids of heart and artery tissue from warm and cold acclimated animals. @entity1426 was the @entity844 precursor found in greatest abundance in both groups. For cardiovascular experiments, bullfrogs were cannulated by using a T-cannula implanted in the right sciatic artery. In warm acclimated bullfrogs, preinfusion systemic arterial pressure (SAP) was 14.7 +/- 0.5 mm Hg, and heart rate was 33.0 +/- 1.7 beats/min. Cold acclimated bullfrogs had SAP values of 8.0 +/- 0.8 mm Hg, and heart rate was 6.9 +/- 0.3 beats/min. Arachidonic and @entity7784 infusions (2,000 micrograms/kg body weight [bw]) were @entity101 in cold acclimated and @entity551 in warm acclimated animals. These effects were blocked by @entity3352 (4 mg/kg bw). In both warm and cold acclimated bullfrogs, @entity3774 (3-100 micrograms/kg bw) was @entity101 , while @entity4770 (0.03-3 micrograms/kg bw) was @entity551 , with both @entity2918 stimulating a greater absolute response in warm acclimated animals. In addition, both @entity2918 increased heart rate in warm but not in cold acclimated bullfrogs. The results suggest diminished cardiovascular sensitivity to @entity2918 at low environmental temperatures.
