Key result
Lumbar sympathetic nerves are not involved in the regulation of blood flow to the hindlimb or systemic blood pressure during anaphylactic hypotension in anesthetized rats.
Why the study?
Does lumbar sympathetic nerve activity regulate skeletal muscle blood flow during anaphylactic hypotension in anesthetized rats?
Does lumbar sympathetic nerve activity regulate skeletal muscle blood flow during anaphylactic hypotension in anesthetized rats?
Lumbar sympathetic nerves do not regulate hindlimb blood flow or systemic blood pressure during anaphylactic hypotension in anesthetized rats.
Caution against extrapolating rat findings to human anaphylaxis; leaves open sympathetic roles in conscious models or other species.
During hypovolemic shock, skeletal muscle blood flow could be redistributed to vital organs via vasoconstriction in part evoked by activation of the innervating sympathetic nerve activity. However, it is not well known whether this mechanism operates during anaphylactic shock. We determined the femoral artery blood flow (FBF) and lumbar sympathetic nerve activity (LSNA) mainly regulating the hindquater muscle blood flow during anaphylactic hypotension in anesthetized rats. Anesthetized Sprague-Dawley rats were randomly allocated to the following groups (n = 7/group): (1) non-sensitized, (2) anaphylaxis, (3) anaphylaxis-lumbar sympathectomy (LS) and (4) anaphylaxis-sinoaortic denervation (SAD) groups. Anaphylaxis was induced by an intravenous injection of the ovalbumin antigen to the sensitized rats. The systemic arterial pressure (SAP), heart rate (HR), central venous pressure (CVP), FBF and LSNA were continuously measured. In the anaphylaxis group, LSNA and HR increased, while SAP and FBF decreased after antigen injection. In the anaphylaxis-SAD group, LSNA did not significantly change during the early phase, but the responses of SAP and FBF were similar to those in the anaphylaxis group. In the anaphylaxis-LS group, both FBF and SAP decreased similarly to the anaphylaxis group during anaphylactic hypotension. These results indicated that LSNA increased via baroreceptor reflex, but this sympathoexcitation or LS did not affect antigen-induced decreases in FBF or SAP. Lumbar sympathetic nerves are not involved in regulation of the blood flow to the hindlimb or systemic blood pressure during anaphylactic hypotension in anesthetized rats.
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Song et al. (2016) studied Anaphylactic hypotension (n=28). Lumbar sympathectomy (LS) or sinoaortic denervation (SAD) during anaphylaxis vs. Anaphylaxis without denervation and non-sensitized controls was evaluated on Femoral arterial blood flow (FBF) and systemic arterial pressure (SAP) during anaphylactic hypotension. Lumbar sympathetic nerves are not involved in the regulation of blood flow to the hindlimb or systemic blood pressure during anaphylactic hypotension in anesthetized rats.
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