Intragastric (IG) administration of probiotic strain Lactobacillus casei Shirota (LcS) decreases the sympathetic nerve outflow of anesthetized rats in a tissue-specific manner. In the present study, we examined the effects of IG administration of LcS on sympathetic activation induced by an intracerebroventricular (ICV) injection of corticotrophin-releasing factor (CRF) and an intravenous (IV) injection of 2-deoxy-d-glucose (2DG) or interleukin (IL)-1β in urethane-anesthetized rats. The IG administration of LcS differently affected the stimulatory responses of sympathetic nerve outflow to CRF. LcS suppressed the increase in splenic sympathetic nerve activity (Spleen-SNA), induced by central CRF, in a dose-dependent manner; however, it did not alter adrenal sympathetic nervous activity (ASNA). In contrast, LcS did not affect spleen-SNA and ASNA following an IV injection of IL-1β. On the other hand, IG administration of LcS suppressed the activation of ASNA following an IV injection of 2DG. These findings suggest that the suppression of central CRF-induced sympathetic activation by LcS is tissue-specific. Moreover, it can suppress the 2DG-induced sympathetic activation. Furthermore, we found that stomach-specific vagotomy attenuates the suppressive effect of LcS on CRF-mediated spleen-SNA activation. Thus, the present study suggests that LcS administered to the stomach may act on the afferent vagal nerve and send afferent signals to the brain to regulate efferent SNA induced by sympathetic stimulators.
Keywords: Adrenal gland; Autonomic nerves; Hypothalamus; Probiotics; Spleen.
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