Reflex changes in post‐ and preganglionic sympathetic adrenal nerve activity and postganglionic sympathetic renal nerve activity upon arterial baroreceptor activation and during severe haemorrhage in the rat

• Published in: Acta Physiologica Scandinavica
• Main Authors: CARLSSON, S., SKARPHEDINSSON, J. O., DELLE, M., HOFFMAN, P., THOREN, P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1992
• Subjects: Physiology; Iceland
• Online Access: http://dx.doi.org/10.1111/j.1748-1716.1992.tb09300.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-1716.1992.tb09300.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-1716.1992.tb09300.x

C arlsson , S., S karphedinsson , J. O., D elle , M., H offman , P. & T horén , P. 1992. Reflex changes in post‐ and preganglionic sympathetic nerve activity and postganglionic sympathetic renal nerve activity upon arterial baroreceptor activation and during severe haemorrhage in the rat. Acta Physiol Scand 144 , 317–323. Received 19 August 1 991 , accepted 18 November 1991. ISSN 0001–6772. Department of Physiology, University of Göteborg, Sweden and Department of Physiology, University of Iceland, Reykjavik, Iceland. The aim of the study was to compare pre‐ (pre‐aSNA) and postganglionic adrenal sympathetic nerve activity (post‐aSNA) and postganglionic renal sympathetic nerve activity (rSNA) in rats during arterial baroreceptor activation and haemorrhage. Adrenal multifibre nerve activity was recorded in chloralose‐anaesthetized Wistar rats. To test for pre‐aSNA or post‐aSNA in adrenal nerves, a ganglionic blocker, trimethaphan (10 mg kg ‐1 ), was administered i.v. If the nerve activity in the adrenal nerve decreased or increased the nerve was considered to contain predominantly post‐or preganglionic fibres, respectively. In contrast, the renal nerves exhibit an almost pure postganglionic activity. Baroreceptor activity was tested by activation of baroreceptors, with an a‐receptor agonist, phenylephrine, which was slowly infused (0.5–2 mUg kg ‐1 min‐ l ), and to deactivate the baroreceptors the rats were bled down to 50 mmHg for 8 min. The experiments showed that all tested nerve types were baroreceptor dependent. There were no significant differences between the slopes relating nerve activity inhibition to increase in blood pressure (infusion of phenylephrine). During maximal inhibition there was a difference between the rSNA and pre‐aSNA, 87 ± 4%, n = 6 , and 68±6%, n = 10 ( P < 0.01) of the control value, respectively. The maximal inhibition of post‐aSNA was 80 ± 3%, n = 7 , of the control value. During haemorrhage there was a difference between the nerve populations. Pre‐aSNA responded with a ...