The role of pulmocutaneous baroreceptors in the control of lymphatic heart rate in the toad Bufo marinus.
The influence of increased pulmocutaneous arterial systolic pressure on amphibian lymph heart activity was determined in Bufo marinus. Arginine vasotocin-induced increases in systolic arterial pressure of greater than 0.5 kPa significantly (P<0.0002) decreased lymph heart rate. Denervation of the recurrent laryngeal nerve led to an increase in arterial pressure of 3.88 kPa in test animals compared to control animals. Denervation abolished lymph heart response to increased arterial pressure for an average of 38 min. Direct stimulation to the recurrent laryngeal nerve stopped lymph heart activity without an increase in arterial pressure. These data indicate that baroreceptors in the pulmocutaneous artery can decrease lymph heart rate during periods of either direct stimulation or elevated arterial pressure. The data also support lymph hearts as effectors for aortic and carotid baroreceptors.
Crossley
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Department of Biology, Portland State University, Oregon 97207-0751, USA. dc0015@unt.edu
Hillman
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D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002024:Bufo marinus / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D007823:Laryngeal Nerves / Q000502:physiology; D008208:Lymphatic System / Q000502:physiology*; D011311:Pressoreceptors / Q000502:physiology*; D014668:Vasotocin / Q000494:pharmacology
D014668:Vasotocin