Oxygen Inhibits Neuronal Activation in the Trigeminocervical Complex After Stimulation of Trigeminal Autonomic Reflex, But Not During Direct Dural Activation of Trigeminal Afferents

Abstract

Objective.-To understand the mechanism of action of oxygen treatment in cluster headache. Background.-Trigeminal autonomic cephalalgias, including cluster headache, are characterized by unilateral head pain in association with ipsilateral cranial autonomic features. They are believed to involve activation of the trigeminovascular system and the parasympathetic outflow to the cranial vasculature from the superior salivatory nucleus (SuS) projections through the sphenopalatine ganglion, via the greater petrosal nerve of the VIIth (facial) cranial nerve. Cluster headache is remarkably responsive to treatment with oxygen, and yet our understanding of its mode of action is unknown.Methods. Conclusions.-The data provide the first systematic, experimental evidence for a mechanism of action of oxygen in cluster headache. The data show oxygen has no direct effect on trigeminal afferents, acting specifically on the parasympathetic/facial nerve projections to the cranial vasculature to inhibit both evoked trigeminovascular activation and activation of the autonomic pathway during cluster headache attacks. Moreover, the studies begin to characterize a novel laboratory model for the most painful primary headache syndrome known -cluster headache.

Neurostimulation in cluster headache: A review of current progress

“…The acute effect of high frequency (80-120 Hz) stimulation of the SPG on the CH attack is likely by a completely different mechanism, possibly by inhibiting parasympathetic outflow, or in an antidromic fashion blocking connections from the SSN and the hypothalamus (100). The importance of the SSN in the pathophysiology of CH has been established relatively recently (87). The dramatic effect seen within minutes may be attributable to a disruption of abnormal electrical or neurochemical activity causing CH.…”

“…It contains sensory, motor and autonomic fibers, of which only the parasympathetic nerves synapse in the ganglion. Its implication in the pathophysiology of CH is well recognized (11,87,88).…”

Sphenopalatine ganglion neuromodulation in migraine: What is the rationale?

“…Inhibiting the activation of the trigeminal afferents may also cancel out triggering of the trigemino-autonomic reflex, thus hindering CAS presentation. Interestingly, Akerman et al (64) have shown that low-frequency stimulation of the SSN in cats leads to firing of trigeminovascular neurons in the trigeminocervical complex as well as increased blood flow to the lacrimal sac, mediated by increased parasympathetic output. This response emphasizes the prospect that high-frequency SPG stimulation may decrease parasympathetic output, thereby inhibiting the excitatory action on trigeminal nociceptors to alleviate migraine pain and associated autonomic symptoms.…”

Effects of Electroacupuncture to the Trigeminal Nerve Area on the Autonomic Nervous System and Cerebral Blood Flow in the Prefrontal Cortex

“…4 The afferents of the trigeminal nerve input synapse onto the trigemino-cervical complex of the upper cervical cord, which activates the parasympathetic reflex through the sphenopalatine ganglion via the superior salivatory nucleus, dilating blood vessels. 5 In addition, studies have noted that the noradrenergic nerve region of the coeruleus nucleus and the serotonergic nerve region of the raphe nuclei constrict cerebral blood vessels, while the cholinergic nerve region in the nucleus basalis of Meynert dilates cerebral blood vessels. 6 Manual acupuncture (MA) and electroacupuncture (EA) have been used to study the autonomic nervous system.…”

“…2 The autonomic nervous system and afferent nerves of the trigeminal nerve area participate in adjusting flow through diverging cerebral arteries in the prefrontal cortex. [3][4][5] The sympathetic nervous system constricts cerebral blood vessels via cervical sympathetic nerves, 3 and the parasympathetic nervous system dilates the cerebral vasculature through the action of the facial nerve via the sphenopalatine ganglion. 4 The afferents of the trigeminal nerve input synapse onto the trigemino-cervical complex of the upper cervical cord, which activates the parasympathetic reflex through the sphenopalatine ganglion via the superior salivatory nucleus, dilating blood vessels.…”