Interaction of Synthetic Peptide Octarphin with Rat Myocardium Membranes

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Y. N. Nekrasova¹, Y. A. Zolotarev², and E. V. Navolotskaya^1*

¹Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, pr. Nauki 6, 142290 Pushchino, Moscow Region, Russia; fax: (4967) 330-527; E-mail: navolotskaya@fibkh.serpukhov.su; elenanavolots@gmail.com

²Institute of Molecular Genetics, Russian Academy of Sciences, pl. Kurchatova 2, 123182 Moscow, Russia; fax: (495) 196-0221; E-mail: zolya@img.ras.ru

^* To whom correspondence should be addressed.

Received April 19, 2011; Revision received May 21, 2011

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A selective agonist of non-opioid β-endorphin receptor synthetic peptide octarphin (TPLVTLFK, specific activity 28 Ci/mmol) was prepared. The [³H]octarphin binding to rat myocardium membranes before and after experimental myocardial infarction (EMI) was studied. It was found that [³H]octarphin with high affinity and specificity binds to non-opioid β-endorphin receptor of rat myocardium membranes before EMI: K_d1 value of the [³H]octarphin specific binding to membranes was 1.8 ± 0.2 nM. In 3 h after EMI a sharp lowering in affinity of the binding is observed (K_d2 = 13.3 ± 0.4 nM), and in 48 h its almost complete restoration (K_d4 = 2.2 ± 0.3 nM). The results indicate participation of non-opioid β-endorphin receptor in the regulation of myocardial activity.

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KEY WORDS: β-endorphin, naloxone, peptide, receptor, myocardium

DOI: 10.1134/S0006297911120066

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