Leptin differentially increases sympathetic nerve activity and its baroreflex regulation in female rats

Role of oestrogen

Zhigang Shi, Virginia Brooks

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Obesity and hypertension are commonly associated, and activation of the sympathetic nervous system is considered to be a major contributor, at least in part due to the central actions of leptin. However, while leptin increases sympathetic nerve activity (SNA) in males, whether leptin is equally effective in females is unknown. Here, we show that intracerebroventricular (i.c.v.) leptin increases lumbar (LSNA) and renal (RSNA) SNA and baroreflex control of LSNA and RSNA in α-chloralose anaesthetized female rats, but only during pro-oestrus. In contrast, i.c.v. leptin increased basal and baroreflex control of splanchnic SNA (SSNA) and heart rate (HR) in rats in both the pro-oestrus and dioestrus states. The effects of leptin on basal LSNA, RSNA, SSNA and HR were similar in males and pro-oestrus females; however, i.c.v. leptin increased mean arterial pressure (MAP) only in males. Leptin did not alter LSNA or HR in ovariectomized rats, but its effects were normalized with 4 days of oestrogen treatment. Bilateral nanoinjection of SHU9119 into the paraventricular nucleus of the hypothalamus (PVN), to block α-melanocyte-stimulating hormone (α-MSH) type 3 and 4 receptors, decreased LSNA in leptin-treated pro-oestrus but not dioestrus rats. Unlike leptin, i.c.v. insulin infusion increased basal and baroreflex control of LSNA and HR similarly in pro-oestrus and dioestrus rats; these responses did not differ from those in male rats. We conclude that, in female rats, leptin's stimulatory effects on SNA are differentially enhanced by oestrogen, at least in part via an increase in α-MSH activity in the PVN. These data further suggest that the actions of leptin and insulin to increase the activity of various sympathetic nerves occur via different neuronal pathways or cellular mechanisms. These results may explain the poor correlation in females of SNA with adiposity, or of MAP with leptin.

Original languageEnglish (US)
Pages (from-to)1633-1647
Number of pages15
JournalJournal of Physiology
Volume593
Issue number7
DOIs
StatePublished - Apr 1 2015

Fingerprint

Baroreflex
Leptin
Estrogens
Estrus
Diestrus
Viscera
Heart Rate
Melanocyte-Stimulating Hormones
Paraventricular Hypothalamic Nucleus
Hypothalamus
Arterial Pressure
Insulin
Intraventricular Infusions
Chloralose
Sympathetic Nervous System
Adiposity
Obesity

ASJC Scopus subject areas

  • Physiology

Cite this

Leptin differentially increases sympathetic nerve activity and its baroreflex regulation in female rats : Role of oestrogen. / Shi, Zhigang; Brooks, Virginia.

In: Journal of Physiology, Vol. 593, No. 7, 01.04.2015, p. 1633-1647.

Research output: Contribution to journalArticle

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