To investigate the properties of ryanodine binding sites of the bird skeletal SR vesicles, SDS PAGE, purification of RyR, and (3H)ryanodine binding study were carried out in the SR vesicles prepared from the chicken pectoral muscle. The chicken SR vesicles have two high molecular weight (HMW) protein bands as in eel SR vesicles on SDS PAGE. The HMW bands on SDS PAGE were found in the (3H) ryanodine peak fraction (Fr3-5) obtained from the purification step of the ryanodine receptor protein. Bmax and KD of the chicken (3H)ryanodine binding sites were 12.52 pmol/mg protein and 14.53 nM, respectively. Specific (3H)ryanodine binding was almost maximal at 50~100 micrometer Ca2+, but was not increased by 5 mM AMP and not inhibited by high Ca2+. Binding was significantly inhibited by 20~100 micrometer ruthenium red and 1 mM tetracaine, but slightly inhibited by Mg2+. From the above results, it is suggested that chicken SR vesicles have the ryanodine binding sites to which the binding of ryanodine is almost maximal at 50~10 micrometer Ca2+, is significantly inhibited by ruthenium red and tetracaine, slightly inhibited by Mg2+, but not affected by AMP and not inhibited by high Ca2+.
Binding Sites* ; Birds ; Chickens* ; Eels ; Electrophoresis, Polyacrylamide Gel ; Molecular Weight ; Ruthenium Red ; Ryanodine ; Ryanodine Receptor Calcium Release Channel ; Sarcoplasmic Reticulum ; Tetracaine

Erectile dysfunction (ED) is a highly prevalent disorder that affects millions of men worldwide. ED is now considered an early manifestation of atherosclerosis, and consequently, a precursor of systemic vascular disease. This study was designed to investigate the effects of male silkworm pupa powder (SWP) on the levels of nitric oxide synthase (NOS) expression, nitrite, and glutathione (GSH); lipid peroxidation; libido; and erectile response of the corpus cavernosum of the rat penis. We induced ED in the study animals by oral administration of 20% ethanol over 8 weeks. The SWP-treated male rats were divided into 3 groups that were orally administered 200, 400, and 800 mg/kg. The libido of the SWP-administered male rats was higher than that of the ethanol control group. In addition, the erectile response of the corpus cavernosum was restored in males on SWP administration, to a level similar to that of the normal group without ED. The testosterone concentration did not increase significantly. The lipid peroxidation in the corpus cavernosum of the male rats administered SWP decreased significantly. In contrast, compared to the ethanol group, SWP-administered male rats showed increased GSH levels in the corpus cavernosum. The level of nitrite and NOS expression in the corpus cavernosum of SWP-administered male rats increased significantly. These results indicated that SWP effectively restored ethanol-induced ED in male rats.
Administration, Oral ; Animals ; Atherosclerosis ; Bombyx ; Erectile Dysfunction ; Ethanol ; Glutathione ; Humans ; Libido ; Lipid Peroxidation ; Male ; Nitric Oxide Synthase ; Penis ; Pupa ; Rats ; Testosterone ; Vascular Diseases