Expression and functions of N-type Cav2.2 and T-type Cav3.1 channels in rat vasopressin neurons under normotonic conditions

The journal of physiological sciences

article

Kaori Sato-Numata¹  Tomohiro Numata²  Yoichi Ueta³  Yasunobu Okada⁴ 

[1] Japan Society for the Promotion of Science;Department of Physiology, School of Medicine, Fukuoka University;Department of Physiology, School of Medicine, University of Occupational and Environmental Health;National Institute for Physiological Sciences

关键词: Cav channel;    Vasopressin neuron;    Flufenamic acid;    Action potential;   

DOI  :  10.1186/s12576-020-00775-w

来源: Springer

【 摘 要 】

Arginine vasopressin (AVP) neurons play essential roles in sensing the change in systemic osmolarity and regulating AVP release from their neuronal terminals to maintain the plasma osmolarity. AVP exocytosis depends on the Ca2+ entry via voltage-gated Ca2+ channels (VGCCs) in AVP neurons. In this study, suppression by siRNA-mediated knockdown and pharmacological sensitivity of VGCC currents evidenced molecular and functional expression of N-type Cav2.2 and T-type Cav3.1 in AVP neurons under normotonic conditions. Also, both the Cav2.2 and Cav3.1 currents were found to be sensitive to flufenamic acid (FFA). TTX-insensitive spontaneous action potentials were suppressed by FFA and T-type VGCC blocker Ni2+. However, Cav2.2-selective ω-conotoxin GVIA failed to suppress the firing activity. Taken together, it is concluded that Cav2.2 and Cav3.1 are molecularly and functionally expressed and both are sensitive to FFA in unstimulated rat AVP neurons. Also, it is suggested that Cav3.1 is primarily involved in their action potential generation.

【 授权许可】

Unknown