Cardiovascular and hidroelectrolytic changes in rats fed with high-fat diet

Area of Science:

• Physiology
• Endocrinology
• Nutrition Science

Background:

• Obesity is linked to hypertension and altered hydroelectrolytic balance.
• The renin-angiotensin system and sympathetic nervous system are activated in obesity.
• Understanding the impact of diet on these systems is crucial for managing obesity-related complications.

Purpose of the Study:

• To investigate the effects of a high-fat diet (HFD) on water intake, urinary excretion, and blood pressure responses to angiotensin II (ANG II) in rats.
• To explore the role of salivation in regulating water intake during HFD.

Main Methods:

• Male Holtzman rats were fed a standard diet (SD) or HFD for 6 weeks.
• Intracerebroventricular (icv) injections of ANG II were administered to assess pressor and dipsogenic effects.
• Daily water intake, urinary excretion, and prandial water consumption were measured.
• The effect of atropine on salivation and water intake was evaluated.

Main Results:

• HFD potentiated the pressor response to icv ANG II but did not alter the dipsogenic response.
• Daily water intake and urinary volume were reduced in HFD-fed rats.
• Prandial water consumption was reduced in HFD-fed rats, an effect reversed by blocking salivation.
• Sodium excretion remained unchanged in HFD-fed rats.

Conclusions:

• HFD potentiates the pressor effects of central ANG II without affecting water intake responses.
• Reduced water intake and urinary volume in HFD-fed rats are observed, independent of sodium excretion changes.
• Salivation appears to play a significant role in the reduced water intake associated with HFD.