Novel method for localized, functional sympathetic nervous system denervation of peripheral tissue using guanethidine

Area of Science:

• Physiology
• Pharmacology
• Neuroscience

Background:

• The sympathetic nervous system regulates peripheral tissues.
• Targeted denervation techniques are crucial for studying tissue-specific sympathetic function.
• Existing methods for sympathectomy can lack specificity or cause systemic effects.

Purpose of the Study:

• To describe and validate a simple technique for local chemical sympathectomy using guanethidine.
• To assess the efficacy and specificity of guanethidine for sympathectomy in white adipose tissue (WAT) and spleen.
• To compare guanethidine's effectiveness against other sympathectomy methods.

Main Methods:

• Microinjections of guanethidine or saline into hamster inguinal WAT (IWAT), epididymal WAT (EWAT), and spleen.
• Assessed sympathetic innervation by measuring norepinephrine (NE) tissue content and WAT pad mass.
• Compared guanethidine with anti-dopamine-beta-hydroxylase saporin and surgical denervation.

Main Results:

• Guanethidine injections effectively abolished sympathetic innervation in IWAT and EWAT, indicated by reduced NE levels and increased WAT mass.
• Local guanethidine treatment resulted in functional sympathectomy of the spleen, evidenced by NE depletion.
• Guanethidine demonstrated greater efficacy than saporin or surgical denervation in reducing IWAT NE content and increasing IWAT mass.
• No systemic effects like body mass reduction, ptosis, or contralateral tissue denervation were observed.

Conclusions:

• Local chemical sympathectomy with guanethidine is an effective and restricted method for targeting peripheral tissues.
• Guanethidine provides a precise tool for sympathectomizing WAT, spleen, and potentially other peripheral organs.
• This technique offers a valuable alternative for studying the role of sympathetic innervation in localized physiological processes.