Ventromedial preoptic prostaglandin E2 activates fever-producing autonomic pathways

Area of Science:

• Neuroscience
• Physiology

Background:

• Fever is induced by pyrogenic cytokines, leading to prostaglandin E2 (PGE2) production in the preoptic area (POA).
• The precise cellular targets and neural pathways of PGE2 in fever remain unclear.
• Understanding these mechanisms is crucial for comprehending thermoregulation and fever pathologies.

Purpose of the Study:

• To map fever-producing sites within the POA using prostaglandin E2 (PGE2).
• To identify neural activation patterns associated with PGE2-induced fever.
• To compare PGE2-induced neural activation with patterns from systemic immune stimulation.

Main Methods:

• Developed a novel method combining acute brain injections with Fos immunohistochemistry.
• Microinjected a threshold dose of PGE2 to map fever-producing sites in the POA.
• Analyzed Fos expression patterns to identify activated neural pathways.

Main Results:

• Identified specific fever-producing sites clustered in the ventromedial POA, near the organum vasculosum of the lamina terminalis.
• Observed Fos induction in the ventromedial POA and parvicellular subnuclei of the paraventricular nucleus of the hypothalamus (PVH) following PGE2 injection.
• Found distinct Fos patterns compared to systemic lipopolysaccharide administration, notably excluding circumventricular organs and magnocellular PVH.

Conclusions:

• Established a potential site of PGE2 action within the POA for fever induction.
• Defined candidate neural pathways involved in PGE2-mediated fever.
• Provided new insights into the neurobiological underpinnings of fever and thermoregulation.