抄録
Our lab reported that LP by 10hPa aggravated pain-related behaviors in chronic pain rats, and this effect was blocked by surgical lumbar sympathectomy. LP also increased systemic blood pressure (BP) and heart rate (HR) in unanesthetized normal rats. Therefore, we hypothesize that SNA plays an important role in pain-aggravation by LP. To prove this hypothesis, I directly recorded SNA in decerebrated rats and examined its change by LP. Normal male SD rats (BW 350-450g) were decerebrated rostral to the superior colliculus under pentobarbital anesthesia. SNA was recorded from the left sympathetic nerve trunk between L3 and L5. LP exposure (30hPa / 10min) was done after removal of anesthesia and under artificial ventilation after immobilization with gallamine. LP tended to increase lumbar SNA and HR. However, these changes were not reversible during observation period (–1.5hr), and no significant change in BP was induced by LP. Increased SNA and HR during LP in decerebrated rats are consistent with the previous observation in normal conscious rats. Our preliminary experiment with decerebrated rats without abdominal surgery for SNA recording, showed reversible increases in BP and HR during LP. This might indicate that abdominal surgery might be the cause of no BP change and irreversibility in HR and SNA changes. [J Physiol Sci. 2007;57 Suppl:S195]
