Functional organization of autonomic neural pathways

Abstract

There is now abundant functional and anatomical evidence that autonomic motor pathways represent a highly organized output of the central nervous system. Simplistic notions of antagonistic all-or-none activation of sympathetic or parasympathetic pathways are clearly wrong. Sympathetic or parasympathetic pathways to specific target tissues generally can be activated tonically or phasically, depending on current physiological requirements. For example, at rest, many sympathetic pathways are tonically active, such as those limiting blood flow to the skin, inhibiting gastrointestinal tract motility and secretion, or allowing continence in the urinary bladder. Phasic parasympathetic activity can be seen in lacrimation, salivation or urination. Activity in autonomic motor pathways can be modulated by diverse sensory inputs, including the visual, auditory and vestibular systems, in addition to various functional populations of visceral afferents. Identifying the central pathways responsible for coordinated autonomic activity has made considerable progress, but much more needs to be done.

Long noncoding NONRATT021972 siRNA normalized abnormal sympathetic activity mediated by the upregulation of P2X7 receptor in superior cervical ganglia after myocardial ischemia

“…Cervical sympathetic ganglia innervate the myocardium and participate in sympathoexcitatory transmission [39][40][41]. The sympathetic nerves from the SCG release ATP through exocytosis [12,19,26].…”

“…In contrast, the parasympathetic action of the vagal nerves in the cardiovascular tissues is inhibitory and decreases the heart rate and cardiac contractions [40][41][42]. The sympathetic and parasympathetic branches of the cardiac autonomic nervous system (ANS) work in a reciprocal fashion to modulate cardiac function primarily through actions on the cardiac pacemaker tissue [40,41].…”

“…In contrast, the parasympathetic action of the vagal nerves in the cardiovascular tissues is inhibitory and decreases the heart rate and cardiac contractions [40][41][42]. The sympathetic and parasympathetic branches of the cardiac autonomic nervous system (ANS) work in a reciprocal fashion to modulate cardiac function primarily through actions on the cardiac pacemaker tissue [40,41]. The ANS balance is driven by both sympathetic and parasympathetic activity and results from reciprocal sympathetic control, reciprocal parasympathetic control, coinhibition, and coactivation [40,41,43].…”

Ballistic stretch or aerobic warm-up evoke postexercise hypotension after maximal exercise

“…The responses of the autonomic nervous system are target specific, i.e. a stimulus is capable of changing the activity of sympathetic nerves that project to one region, with no changes in the overall sympathetic activity 30 , therefore the direct sympathetic stimulus to the muscle cannot be assessed through HRV analysis and possibly influenced the results.…”

“…This hypothesis further elucidation, since the plasmatic levels of these hormones were not directly measured in this study. Alternatively, the control of blood pressure after maximal exercise may be due to specific autonomic afferents to the exercised region, rather than an indiscriminate all-or-none autonomic excitation 30 , therefore affecting muscular autonomic activity differently from the heart, which would not be efficiently assessed by HRV.…”