Cacna1f gene decreased contractility of skeletal muscle in rat model with congenital stationary night blindness

Abstract

The CACNA1F gene encodes a member of the alpha-1F subunit family in the voltage-dependent calcium channel (Cav1.4) complex. Mutations in this gene result in incomplete congenital stationary night blindness (iCSNB2) in humans. And Cav1.4 mutation could affect the functions of the skeletal muscle. This study investigated the role of Cacna1f mutations in alteration of the skeletal muscle functions in a Cacna1f mutation rat model (Cacna1fCSNB2 rat). We found that the muscle endurance behaviors of Cacna1fCSNB2 rats were significantly lower than those of the wild-type rats. The high-frequency fatigue resistance of the soleus muscle was decreased in Cacna1fCSNB2 rats under continuous tetanic stimulation. The expression levels of the syntaxin (SYN) proteins in the soleus of the Cacna1fCSNB2 rats were lower than those of wild-type rats. SYN was expressed in the soleus muscle, but not in the extensor digitorum longus. The Cav1.4 protein was not detected in the skeletal muscle of Cacna1fCSNB2 rats. The Cacna1f mRNA level in the soleus of Cacna1fCSNB2 rats was decreased compared with that in wild-type rats. This study demonstrated for the first time that the Cacna1f mutation reduces the function of slow-twitch skeletal muscle. And it also demonstrated that the Cacna1f gene affects synapse-associated protein expression, which may block the signal transmission in synaptic connectivity of the retina and skeletal muscle in Cacna1f-mutant rats.