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Changes in baroreflex sensitivity lag changes in blood pressure during entry into and arousal from hibernation in the Syrian hamster
Author(s) -
Gorgone Julia Victoria,
Chau Sat M,
Hamilton Jock S,
Horowitz John M,
Horwitz Barbara A,
Chen ChaoYin
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1075.12
Subject(s) - hibernation (computing) , baroreflex , heart rate , blood pressure , medicine , baroreceptor , endocrinology , chemistry , biology , state (computer science) , algorithm , computer science
Entry into hibernation involves resetting homeostatic regulation of core temperature, respiration rate, blood pressure (BP), and heart rate (HR) to conserve energy. We tested the hypothesis that baroreflex sensitivity (BRS) also decreased during entry into hibernation by continuously measuring BP and HR via telemetry transmitters implanted in the aorta of 4 Syrian hamsters. After at least 12 days recovery in a 14:10 Light:Dark cycle at 23°C, hamsters were moved to an 8:16 Light:Dark cycle at 6 ± 1°C. They maintained BP at 102 ± 5 mmHg, HR at 301 ± 14 bpm, and BRS at −14 ± 3 bpm/mmHg while euthermic, but after the first 2 hrs of their entry into hibernation, BP and HR had significantly decreased (54 ± 14 mmHg, 61 ± 19 bpm, respectively) while BRS was maintained (−11 ± 2 bpm/mmHg). During the next 3–4 hrs of entry, BP and HR continued to decrease, with BRS falling as well (−3 ± 1 bpm/mmHg). During arousal from hibernation, BRS recovery also lagged behind BP and HR – i.e., in the initial stage of spontaneous arousal (~1.5hrs), BP increased to pre‐hibernation levels (102 ± 12 mmHg), HR partially recovered (108 ± 51 bpm), but BRS remained low (−4 ± 2 bpm/mmHg). Approximately 1 hr later, BRS and HR had returned to pre‐hibernation levels. This ~ 2 hr lag between changes in BRS and those of BP indicates distinct phases in resetting cardiovascular regulation during entry into and arousal from hibernation. (Support: R01 HL091763 )