ABSTRACT
The effect of carbachol (80 nmol/microliters) injection into the amygdaloid nuclear complex (AMG) on sodium appetite and water intake was studied in male Holtzman rats weighing 240-270 g. Twenty-five satiated rats and 38 water-deprived rats were used in the experiment on water intake. In the experiment on sodium intake, 19 rats were injected with atropine+carbachol and 9 rats with hexamethonium+carbachol. After carbachol injection into the AMG, water intake decreased in rats submitted to 30 h of water deprivation (10.28 +/- 1.04 ml/120 min vs 0.69 +/- 0.22 ml/120 min). The decrease in water intake was blocked by prior local injection of atropine (20 nmol/l microliters) (11.66 +/- 1.46 ml/120 min vs 0.69 +/- 0.22 ml/120 min), but not of hexamethonium (30 nmol/1 microliters), into the AMG. In water-deprived animals, carbachol injection into the AMG caused a decrease in sodium chloride intake (6.16 +/- 1.82 ml/h vs 0.88 +/- 0.54 ml/h) which was blocked by previous injection of hexamethonium but not of atropine. These results suggest that the cholinergic system of the AMG plays a role in the control of water and salt intake.
Subject(s)
Amygdala/drug effects , Carbachol/pharmacology , Drinking/drug effects , Parasympatholytics/pharmacology , Sodium Chloride, Dietary , Amygdala/physiology , Animals , Atropine/administration & dosage , Carbachol/administration & dosage , Hexamethonium , Hexamethonium Compounds/administration & dosage , Injections , Male , Parasympatholytics/administration & dosage , Rats , Water DeprivationABSTRACT
The effect of carbachol (80 nmol/microliters) injection into the amygdaloid nuclear complex (AMG) on sodium appetite and water intake was studied in male Holtzman rats weighing 240-270 g. Twenty-five satiated rats and 38 water-deprived rats were used in the experiment on water intake. In the experiment on sodium intake, 19 rats were injected with atropine+carbachol and 9 rats with hexamethonium+carbachol. After carbachol injection into the AMG, water intake decreased in rats submitted to 30 h of water deprivation (10.28 +/- 1.04 ml/120 min vs 0.69 +/- 0.22 ml/120 min). The decrease in water intake was blocked by prior local injection of atropine (20 nmol/l microliters) (11.66 +/- 1.46 ml/120 min vs 0.69 +/- 0.22 ml/120 min), but not of hexamethonium (30 nmol/1 microliters), into the AMG. In water-deprived animals, carbachol injection into the AMG caused a decrease in sodium chloride intake (6.16 +/- 1.82 ml/h vs 0.88 +/- 0.54 ml/h) which was blocked by previous injection of hexamethonium but not of atropine. These results suggest that the cholinergic system of the AMG plays a role in the control of water and salt intake.
Subject(s)
Animals , Male , Rats , Amygdala/drug effects , Carbachol , Drinking/drug effects , Parasympatholytics/pharmacology , Sodium Chloride, Dietary , Amygdala/physiology , Atropine , Carbachol , Hexamethonium Compounds/administration & dosage , Hexamethonium , Injections , Parasympatholytics/administration & dosage , Water DeprivationABSTRACT
Se encontró el conocido patrón de dos etapas de facilitación y depresión de las respuestas posganglionares a estimulación de alta frecuencia (24 Hz) de los nervios preganglionares. Se observó que la etapa de depresión estaba exagerada bajo bloqueo parcial con hexametonio, pero que no la afectaba la sección transversa parcial del tronco preganclionar. A frecuencia baja (8 Hz) el reclutamiento normal se tornaba en el patrón familiar de dos etapas bajo dosis moderadas de hexametonia. La evolución de la depresión bajo los efectos del antagonista nicotínico competitivo dihidro-ß-eritroidina fue muchísimo más lenta que bajo la acción del hexametonio. Estas observaciones pueden atribuirse al conocido efecto de consumo y dependencia del hexametonio