The Role of Potassium Channels in the Regulation of the Transport Function of Rats Lymph Nodes during Inflammation

Abstract

Lymph formed in tissues necessarily passes through lymph nodes (LN), which not only perform an immune function, but also take part in lymph flow through rhythmic high-amplitude contractions. During inflammation, inducible NO synthase (iNOS) is expressed in the lymph nodes, which promotes relaxation of the LN capsule. This study examined the role of KATP- and BKCa-channels in sepsis-induced LN remodeling. Sepsis was induced in rats by cecal ligation-puncture surgery. After 12 and 24 h, mesenteric LN were removed and examined in a myograph. KATP-channels were activated by pinacidil and blocked by glibenclamide. BKCa-channels blocked TEA and activated NS 1619. The strength of tonic contraction of the LN under the action of activators and blockers was assessed. LN of septic rats named low level of tone during standard stretching. Pinacidil led to greater relaxation of LN in septic rats compared to the control group; the effect of glibenclamide was accompanied by an increase in tone. Pinacidil combined with glibenclamide did not lead to significant changes in LN tone. The use of NS 1619 was accompanied by relaxation of the LN; in the LN of septic rats, the effect was more pronounced. TEA (3 mM) led to an increase in LN tone; the LN of septic rats responded to the use of TEA with a greater contraction. We concluded that NO produced by expressed iNOS in animals with sepsis directly or indirectly activates KATP- and BKCa-channels of smooth muscle cells of the capsule in the LN, which leading to hyperpolarization of the smooth muscle cell membrane and their relaxation, which that promotes relaxation of the LN capsule and their hypertrophy of LN. In the future, KATP- and BKCa-channels of smooth muscle cells of the lymph node LN capsule may be a potential target for therapeutic intervention to correct the immune response by slowing down or accelerating the flow of lymph through the LN.