Abstract:The surgical stress response is the neurophysiologic reflex response to surgery, which involves activation of the hypothalamic-pituitary-adrenal axis and is regulated by the hypothalamic paraventricular nucleus. The effect of preoperative use of local anaesthetics on activation of neurones in the paraventricular nucleus during surgery was studied by quantification of the neuronal expression of the c-fos-gene after a standardized plantar incision in rats. Furthermore, cfos expression in the spinal dorsal horn was used as a measure of spinal nociception. Six halothane-anaesthetized animals underwent surgery following infiltration with lidocaine and bupivacaine, six animals were operated without local anaesthetics, and six control animals were subjected to the anaesthetic procedures. After two hours, the animals were perfused with 4% formaldehyde and the spinal cords and brains were collected and processed by immunohistochemistry for stereological quantification of the number of neurones with Fos-like immunoreactivity. Furthermore, brain and spinal cord were sampled from nine control animals right after induction of halothane anaesthesia. Surgery without local anaesthetics caused a significant increased number of neurones with Fos-like immunoreactivity in the spinal cord (4258∫1710; mean∫S.D.; PϽ0.01) compared to the anaesthesia control group (1204∫436). Local anaesthetics reduced this number to 2029∫919 (PϽ0.05), which was not significantly different from the anaesthesia control group. After surgery, the number of neurones with Fos-like immunoreactivity in paraventricular nucleus increased from 2948∫1365 in the anaesthetized control group to 5550∫3875 and 5191∫1558 in the surgery and local anaesthetics plus surgery group, respectively, although significance was only reached for the group receiving local anaesthetics (PϽ0.05). In conclusion, preoperative local anaesthetic infiltration did not reduce the surgery-induced c-fos expression in paraventricular nucleus after paw surgery in rats, although spinal nociception was reduced.Post-operative complications, leading to increased morbidity and mortality, are common problems after surgery (Holte & Kehlet 2002). Some of these complications can be ascribed to the surgical stress response (Kehlet 1988), which is defined as the neurophysiologic reflex response to surgery involving activation of the hypothalamic-pituitary-adrenal axis (Wilmore et al. 1976;Herman & Cullinan 1997), implying extensive hormonal and metabolic changes (Kehlet 1984;Chrousos 1998;Desborough 2000). Thus, activated neurones in the hypothalamic paraventricular nucleus synthesize and release corticotrophin-releasing factor, which via secretion of adrenocorticotrophic hormone (ACTH) from the pituitary gland initiates release of cortisol (corticosterone in rats) from the adrenal cortex. Activation of neurones in the paraventricular nucleus is associated with expression of the immediate-early gene c-fos, which consequently has been used as a marker of stress . Similarly, c-fos expression in neur...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.