Electrical stimulation-induced alpha1- and alpha2-adrenoceptors-mediated contractions of isolated canine lymph nodes

Involvement of α-adrenoceptors to the implementation of the contractile effects in the capsule of mesenteric lymph nodes in response to electrostimulation

We studied changes in the contractile function of smooth muscle cells in bovine mesenteric lymph node capsule caused by electrical stimulation of nerve fibers in vitro. It was found that electrostimulation increased tonic tension and frequency of smooth muscle contractions in the node capsule. Tetrodotoxin prevented the stimulatory effect of electrical stimulation on the smooth muscle cells. Phentolamine, prazosin, and yohimbine significantly reduced the capsule response to electrical stimulation and norepinephrine application. It was concluded that excitation of nerve fibers in the capsule of bovine mesenteric lymph nodes upon electrical stimulation is realized, at least in part, via activation of α1-adrenoceptors and, to a lesser extent, via α2-adrenoceptors located on the membrane of smooth muscle cells.

Mechanical properties of lymph node capsule

We studied the relationship between the length and tension in isolated strips of the capsules of bovine mesenteric lymph nodes. The deformation-strain and radius-pressure relationships were established in the lymph node. The capsule possesses high distensibility, modulus of elasticity at optimal tension was 0.09×10(5) N/m2. Smooth muscle activation produces a 6-fold increase of modulus of elasticity. Maximum active stress in the capsule was recorded at a length of 1.1 L0 and maximal active pressure (4.5 cm H2O) at 0.9 L0.