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Acute hyperglycemia decreases renal sympathetic nerve activity in conscious rats
Author(s) -
Huber Domitila Augusta,
Fazan Rubens,
Salgado Helio Cesar
Publication year - 2008
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.22.1_supplement.950.1
Subject(s) - mannitol , baroreflex , endocrinology , osmole , blood pressure , osmotic concentration , medicine , chemistry , bolus (digestion) , basal (medicine) , anesthesia , insulin , heart rate , biochemistry
The effect of hyperglycemia on arterial pressure (AP), renal sympathetic nerve (RSN) activity and baroreflex control of RSN activity was investigated in conscious rats. The rats were submitted to surgical procedures under tribromoethanol and the experiments were conducted 6 to 8 hours after the recovery of anesthesia. Intravenous bolus (0.25 mL) administration of glucose 50% (n=10), or mannitol 30% (n=7), followed by continuous infusion (2 mL/h) during 30 min was carried out. RSN activity was evaluated during spontaneous activity (% basal) and by means of pressure‐nerve activity curve normalized as maximum activity (% max) as well. The infusion of glucose increased blood glucose (127±4 to 319±8 mg/dL) and plasma osmolarity (300±1 to 317±2 mOsm/kgH 2 O). The infusion of Mannitol increased the plasma osmolarity (301±2 to 313±3 mOsm/kgH 2 O) without affecting blood glucose (123±4 to 124±5 mg/dL). Glucose did not affect basal AP (108±1 to 106±2 mmHg) but decreased RSN activity (24±5 %). In addition, glucose reduced the range (103±2 to 82±6 % max) and gain (−3.43±0.25 to −2.59±0.30 % max/mmHg) of RSN activity, obtained by means of pressure‐nerve activity curve. Mannitol did not affect any parameter studied. In conclusion, the present study demonstrate, in conscious rats, that acute hyperglycemia promote reduction of spontaneous RSN activity and baroreflex control of RSN as well. Financial Support: CAPES, FAPESP, CNPq.