Species heterogeneity of hepatic alpha 1-adrenoceptors: alpha 1A-, alpha 1B- and alpha 1C-subtypes.
alpha 1-Adrenergic activation stimulated phosphorylase and phosphoinositide turnover in hepatocytes from guinea pigs, rats and rabbits. Chlorethylclonidine inhibited these effects in rat and rabbit cells but not in guinea pig hepatocytes; low concentrations of 5-methyl urapidil blocked the alpha 1 actions in guinea pig and rabbit liver cells, but not in rat hepatocytes. Binding competition experiments also showed high affinity for 5-methyl urapidil in liver membranes from guinea pigs and rabbits and low affinity in those from rats. The data indicated that guinea pig hepatocytes express alpha 1A-, rat hepatocytes alpha 1B- and rabbit hepatocytes alpha 1C- adrenoceptors. This was confirmed by Northern analysis using receptor subtype-selective probes.
García-Sáinz
J A
JA
Instituto de Fisiologia Celular, Universidad Nacional Autónoma de México, D.F.
Romero-Avila
M T
MT
Alcántara Hernández
R
R
Macias-Silva
M
M
Olivares-Reyes
A
A
González-Espinosa
C
C
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D006168:Guinea Pigs; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D013045:Species Specificity
D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; D011942:Receptors, Adrenergic, alpha; C057446:5-methylurapidil; D012313:RNA; D015544:Inositol 1,4,5-Trisphosphate; D011433:Propranolol; D009638:Norepinephrine; D011224:Prazosin