Splanchnic nerve stimulation increases the lymphocyte output in mesenteric efferent lymph

Area of Science:

• Immunology
• Physiology
• Neuroscience

Background:

• Lymphatic system plays a crucial role in immune surveillance.
• Nervous system modulation of immune cell traffic is increasingly recognized.
• Understanding lymphocyte circulation is vital for immune response.

Purpose of the Study:

• To investigate the effect of splanchnic nerve stimulation on mesenteric lymph characteristics.
• To elucidate the role of the autonomic nervous system in lymphocyte trafficking.
• To identify the specific receptors involved in nerve-induced lymph changes.

Main Methods:

• Collection of mesenteric efferent lymph from anesthetized sheep.
• Measurement of lymph flow rate and leukocyte content.
• Stimulation of the left greater splanchnic nerve at 4 Hz.
• Intravenous administration of noradrenaline and phentolamine.

Main Results:

• Splanchnic nerve stimulation significantly increased lymph flow (128%) and white cell count (44%) within the first 5 minutes.
• Overall white cell output in lymph increased by 228% during nerve stimulation.
• Noradrenaline mimicked the effect, while phentolamine blocked it, indicating alpha-adrenoceptor mediation.
• Arterial red blood cell count increased, but white blood cell count and lymphocyte percentage remained unchanged.

Conclusions:

• The sympathetic nervous system, via alpha-adrenoceptors, modulates lymphocyte traffic from the gut.
• This neuro-immune interaction represents a rapid mechanism for altering immune cell distribution.
• Further research is needed to explore the immunological consequences of this phenomenon.