Sympathetic nerve terminals in the tunica media of human superficial temporal and middle cerebral arteries: wet histofluorescence.

Abstract

SUMMARY In specimens from the superficial temporal artery (STA) and middle cerebral artery (MCA), obtained during STA-MCA anastomosis, green fluorescent varicose fibers of sympathetic nerves were clearly visible with both formaldehyde-glutaraldehyde and sucrose-potassium phosphate-glyoxylic acid wethistofluorescent techniques. These fibers were fairly thick, were densely packed and had a meshwork-like arrangement. Fluorescent terminals were seen both in the adventitia and in the outer muscular layer of the media in both STA and MCA specimens. They were more often observed in patients with prominent atherosclerosis in these vessels. The present study suggests the possible role of sympathetic nerve terminals in the development of vasospasm and occlusive lesions in cerebral vessels. It may also help to explain the marked constriction and transient occlusion following a STA-MCA bypass procedure. SUPERFICIAL TEMPORAL ARTERY (STA) -middle cerebral artery (MCA) anastomosis plays a potentially important role in the surgical treatment of ischemic cerebrovascular diseases. STA-MCA anastomosis is not a technically hazardous operation. However, when these vessels are not handled gently during the operation, marked spasm and transient postoperative occlusion are often seen angiographically within the first few days after the bypass procedure.1^ Allen et al. reported in vitro contractile activity of vasoactive agents on human STA and MCA, and postulated that either the sympathetic nerves or serotonin could be the cause of arterial spasm in these segments. 5 However, there have been no histochemical demonstrations of sympathetic nerve terminals in human STA and MCA. We present sympathetic nerve terminals in STA and MCA using wet-histochemical fluorescent techniques and discuss the possible role of these terminals in the development of vasospasm and arterial lesions. Materials and MethodsThe formaldehyde-glutaraldehyde (FaGlu) and sucrose-potassium phosphate-glyoxylic acid (SPG) wethistofluorescent methods are useful because of their simplicity and constant visualization of catecholamine terminal fibers as compared to conventional FalckHillarp histofluorescent methods. 6,7 These methods were used on arterial specimens obtained at surgery. Five MCA and 8 STA specimens were obtained from 8 patients with transient ischemic attacks (TIAs), reversible ischemic neurological deficits, or completed stroke between the ages of 37 and 67 during 9 STA-MCA anastomosis ( in phosphate buffer) or SPG (2% glyoxylic acid and 30% sucrose in phosphate buffer at pH 7.4) mixtures at 0-^4°C for 4-6 hours. They were then processed according to FaGlu 6 and SPG 7 techniques. The specimens were examined and photographed under ultraviolet light (Olympus BH-RFL). ResultsIn the sections from the STA and the cortical branch of MCA, green fluorescent varicose fibers were clearly visible with both FaGlu and SPG techniques. Cathecholamine fluorescence was more clearly visible with the SPG technique than with the FaGlu technique ( fig. 1). Fluorescent varico...

Weakness of Sympathetic Neural Control of Human Pial Compared With Superficial Temporal Arteries Reflects Low Innervation Density and Poor Sympathetic Responsiveness

“…NE ED 50 and E max were not significantly altered by pretreatment with any of these agents (Pϭ. 36 and Pϭ.10, respectively). The contractions to EFS (-2.6% E max at 8 Hz) seen in 5 segments were unaltered by exposure to these drugs.…”

Effect of Adventitial Dissection of Superficial Temporal Artery on the Outcome of Superficial Temporal Artery-Middle Cerebral Artery Bypass in Moyamoya Disease

“…Although the role of the autonomic nerve system in the regulation of cerebral blood flow remains controversial, it has been indicated that decreasing sympathetic tone may offer therapeutic benefit during cerebral vasospasm [28]. A large amount of sympathetic nerve fibers and nerve endings have been found in STA adventitia and fascia [3, 29]. We speculated that the sympathetic control of STA contributes to the hemodynamic instability after STA-MCA bypass.…”

“…STA travels within the temporal muscle fascia, thus, its expansion could be affected mechanically by the adventitia and surrounding fascia. In addition, adventitia and fascia of STA contained a large amount of sympathetic nerve fibers [3]. The sympathetic nerve of the artery may play an important role in vascular tone thus affect the blood flow after the STA-MCA bypass.…”

Density of sympathetic nerve terminals in human superficial temporal arteries: potassium permanganate fixation and monoamine oxidase histochemistry.

“…With a wet fluorescence method the segments of STA's and middle cerebral arteries obtained at IC-EC bypass surgery have shown fluorescent nerve terminals in both the adventitia and the medial layers of those vessels. 5 It is still unclear whether the perivascular nerves are functionally different in different innervated arteries. Morphometric studies of the vesicles included in nerve terminals might give us some clues to understand such a situation.…”