Increased cellular activity in rat insular cortex after water and salt ingestion induced by fluid depletion.
Insular cortex (IC) receives inputs from multiple sensory systems, including taste, and from receptors that monitor body electrolyte and fluid balance and blood pressure. This work analyzed metabolic activity of IC cells after water and sodium ingestion induced by sodium depletion. Rats were injected with the diuretic furosemide (10 mg/kg body wt), followed 5 min later by injections of the angiotensin-converting enzyme inhibitor captopril (5 mg/kg body wt). After 90 min, some rats received water and 0.3 M NaCl to drink for 2 h while others did not. A third group had access to water and saline but was not depleted of fluids. All rats were killed for processing of brain tissue for Fos-immunoreactivity (Fos-ir). Nondepleted animals had weak-to-moderate levels of Fos-ir within subregions of IC. Fluid-depleted rats without fluid access had significantly increased Fos-ir in all areas of IC. Levels of Fos-ir were highest in fluid-depleted rats that drank water and sodium. Fos-ir levels were highest in anterior regions of IC and lowest in posterior regions of IC. These results implicate visceral, taste, and/or postingestional factors in the increased metabolic activity of cells in IC.
Pastuskovas
Cinthia V
CV
Department of Psychology, University of Iowa, Iowa City, Iowa 52242-1407, USA.
Cassell
Martin D
MD
Johnson
Alan Kim
AK
Thunhorst
Robert L
RL
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D003681:Dehydration / Q000503:physiopathology*; D004326:Drinking / Q000502:physiology*; D005786:Gene Expression Regulation; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D051381:Rats; D012965:Sodium Chloride / Q000494:pharmacology*; D014867:Water / Q000494:pharmacology*; D014883:Water-Electrolyte Imbalance / Q000503:physiopathology
D016760:Proto-Oncogene Proteins c-fos; D014867:Water; D012965:Sodium Chloride