Role Of Autonomic Nervous Neurotransmitter On The Expression Of Ca-L And KAch Channels In Rat Atrial Myocytes

Objective: To investigate the effects of different concentrations of autonomic neurotransmitter norepinephrine(NE)and acetylcholine(Ach)on the expression of L-type calcium channel(Ca-L)and acetylcholine sensitivity potassium channel(Kach)related genes and proteins in atrial myocytes of neonatal rats.Methods: The atrial myocytes were isolated from the one-day-old SD rats,and then cultured in 24 h.They were divided into low drug concentration group and high drug concentration group depending on the treatment administered.Each group was divided into 5 subgroups according to the following scheme.(1)Low drug concentration group.Control group: no intervention,24 h of training;NE group: NE 0.1μmol/L intervention for 24 h;Ach group: Ach 0.1μmol/L intervention for 24 h;NE+Ach group: NE 0.1μmol/L+Ach 0.1μmol/L intervention for 24 h;NE+Meto group: NE 0.1 μmol/L+metoprolol(Meto)0.1μmol/L intervention for 24 h.(2)high concentration group.control group: no intervention,training for 72 h;NE group: NE 10μmol/L intervention for 72 h;Ach group: Ach 10μmol/L intervention for 72 h;NE+Ach group: NE 10μmol/L+Ach 10μmol/L intervention for 72 h;NE+Meto group: NE 10μmol/L+metoprolol 10μmol/L intervention for 72 h.Gene expressions of Cav1.2,Cav1.3,Kir3.1 and Kir3.4 were detected by real-time reverse transcriptase-polymerase chain reaction(real-time RT-PCR).Cav1.2,Cav1.3,Kir3.1 and Kir3.4 proteins in whole-cell extracts were assayed by western blot analysis.Results:(1)Low drug concentration group.The m RNA and protein expressions of Cav1.2 and Cav1.3 were up regulated after NE stimulation,and the expression of Kir3.1 and Kir3.4 m RNAs were down regulated.The m RNA and protein expressions of Cav1.2 and Cav1.3 were down regulated after Ach stimulation,and the m RNA expressions of Kir3.1 and Kir3.4 were up regulated in 24 h.In NE+Ach group and NE group,the m RNA and protein expressions of Cav1.2 and Cav1.3 were down regulated,simultaneously,the m RNA and protein expressions of Kir3.1 and Kir3.4 were up regulated.Compared with that in Ach group,the m RNA and protein expressions of Kir3.4 were down regulated in NE+Ach group.Compared with that in NE group,the m RNA and protein expressions of Cav1.2 and Cav1.3 were down regulated after Meto intervention,and the m RNA and protein expressions of Kir3.1 and Kir3.4 were up regulated.(2)High drug concentration group.The m RNA and protein expressions of Cav1.2,Cav1.3,Kir3.1 and Kir3.4 were decreased after stimulation with NE and Ach in 72 h.In NE+Ach group,NE group and Ach group,the protein expressions of Kir3.1 and Kir3.4 were down regulated.In NE+Meto group and NE group,the m RNA and protein expressions of Cav1.2 and Cav1.3 were up regulated,and the protein expressions of Kir3.1and Kir3.4 were down regulated.Conclusion:(1)low concentration of NE promoted the expression of Cav1.2 and Cav1.3 genes and proteins in cultured atrial myocytes of rats,and inhibited the expression of Kir3.1 and Kir3.4,but vagus nerve was the opposite.Meto intervention could inhibit the above effects of NE.(2)high concentration of NE and Ach inhibited the expression of Ca-Lh and KAch channels,Cav1,2,Cav1.3 and Kir3.1,Kir3.4,m RNA and protein.Meto intervention could partially inhibit the above effects.