Intravenous infusion of hexamethonium and atropine but not propranolol diminishes apolipoprotein A-IV gene expression in rat ileum.
To clarify the role of neural factors in the regulation of apolipoprotein (apo) A-IV expression in the small intestine, we investigated the effect of neural blockers on mRNA levels of apo A-IV in rat small intestine. Either ganglionic blocker (hexamethonium), cholinergic blocker (atropine) or beta-adrenergic blocker (propranolol) was infused intravenously to unrestrained conscious rats for 8 h, and then total RNA was isolated from the small intestine and analyzed using Northern hybridization. Apo A-IV mRNA levels in the ileum were significantly lower in hexamethonium- or atropine-infused rats than in saline- (control) or propranolol-infused rats. Immunoblot analysis showed no difference in plasma apo A-IV concentrations between hexamethonium- and saline-infused groups. The lower mRNA levels of apo A-IV in the ileum of hexamethonium-infused rats were observed even in bile-drained rats, indicating that the lower expression was not due to any changes in bile availability. The ileal apo A-IV mRNA levels were significantly higher in rats infused with lipid emulsion into the ileum than in rats infused with glucose-saline, and the concomitant infusion of intravenous hexamethonium did not affect the higher levels of apo A-IV mRNA. These results suggest that the basal expression of the ileal A-IV gene is at least partially regulated in a site-specific manner by cholinergic neurons.
Sonoyama
K
K
Laboratory of Food Biochemistry, Research Group of Food Science, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589 Japan.
Tajima
K
K
Fujiwara
R
R
Kasai
T
T
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants; D001054:Apolipoproteins A / Q000097:blood / Q000187:drug effects* / Q000235:genetics; D001285:Atropine / Q000008:administration & dosage / Q000494:pharmacology*; D005730:Ganglionic Blockers / Q000008:administration & dosage / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D018738:Hexamethonium / Q000008:administration & dosage / Q000494:pharmacology*; D007082:Ileum / Q000187:drug effects; D007262:Infusions, Intravenous; D008297:Male; D010276:Parasympatholytics / Q000008:administration & dosage / Q000494:pharmacology*; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
D000319:Adrenergic beta-Antagonists; D000975:Antioxidants; D001054:Apolipoproteins A; D005730:Ganglionic Blockers; D010276:Parasympatholytics; D012333:RNA, Messenger; C022205:apolipoprotein A-IV; D018738:Hexamethonium; D001285:Atropine; D011433:Propranolol