Feline cerebral veins and arteries: comparison of autonomic innervation and vasomotor responses

Abstract

SUMMARY1. The innervation of feline cerebral (pial) vessels by nerve fibres containing noradrenaline, substance P or vasoactive intestinal polypeptide (VIP) has been examined using the Falck-Hillarp histo-fluorescence method and immunohistochemical techniques. Cerebral veins were shown to be innervated by nerve fibres containing noradrenaline, substance P or VIP. Nerve fibres containing noradrenaline were the most numerous, while fibres containing substance P were observed least frequently in both types of vessel. For each putative neurotransmitter, the density of the innervation of the cerebral veins was less than that of cerebral arteries.2. The vasomotor responses of individual pial arteries and veins on the convexity of the cerebral cortex to perivascular micro-injection of noradrenaline, substance P and VIP were examined in twenty-five cats anaesthetized with a-chloralose.3. The perivascular micro-application of noradrenaline resulted in pronounced dose-dependent reductions in the diameter of pial veins (maximum calibre reduction: 32 + 3 % noradrenaline 10-5 M) and arteries (22 + 3 % noradrenaline 10-5 M). Pial veins were more sensitive to noradrenaline than were pial arteries tested under similar conditions. The reductions in the diameter of cerebral veins and arteries resulting from the administration of noradrenaline could be attenuated by the concomitant micro-application of phentolamine (106 M).4. The perivascular micro-application of substance P effected significant dosedependent increases in the calibre of pial veins (maximum calibre increase: 16 + 4 % substance P 10-7 M) which were of a similar magnitude to those observed in pial arteries in response to this peptide (21 +4 4% substance P 10-6 M).5. The perivascular micro-application of VIP resulted in small increases in the calibre of pial veins (maximum calibre increase: 9 + 2 % VIP 10-8 M) which were proportionately smaller than those observed in pial arteries in response to this peptide (23±5% VIP 10-7 M).

Tachykinins (Substance P, Neurokinin A, Neuropeptide K, and Neurokinin B) in the Cerebral Circulation: Vasomotor Responses in vitro and in situ

“…Removal of the endothelium abolished relaxation induced by all four tachykinins. The relaxant responses of guinea It is well recognized that substance P (SP), which is a peptide involved in the mechanisms of nocicep tion, also produces strong relaxation of cerebral ar teries in vitro and in situ (Edvinsson et al , , 1982. SP is present in afferent nerve fibers (Edvins son et al , 1981(Edvins son et al , , 1982(Edvins son et al , , 1983 originating in trigem inal nerve cell bodies that supply cerebral blood vessels (Liu-Chen et al , 1983a,b).…”

“…Approximately 5 f.Ll of artificial CSF was injected into the perivascular space over 15 s. The maximum changes in vessel caliber following perivascu lar application of peptides were expressed as % changes relative to the diameter of the vessel before drug appli cation, and were compared with those following the ad ministration of artificial CSF alone. For further method ological details, see Edvinsson et al (1981Edvinsson et al ( , 1982.Data are expressed as mean values ±SD of responses of individual arterioles. Differences between the mean values were assessed by Student's t<est with the use of Bonferroni's inequality correction.…”

Reflex-Mediated Reduction in Human Cerebral Blood Volume

“…Sympathetic innervation has been demonstrated in the cerebral arteriolar and venous smooth muscle and is hypothesized to contribute to the regulation of CBV and intracranial pressure Johansson, 1980, 1981). It has also been proposed that cerebral veins may respond to sympathetic stimulation more than the arterial system (Auer and Johansson, 1980;Edvinsson et al, 1982) although both are likely to undergo simultaneous constrictor responses during reflex arousal . Regardless of the mechanism, this study is in agreement with reflexive CBV alterations in mice (Edvinsson et al, 1971) and cats Johansson, 1980, 1981) and indicates a possible mechanism of intracranial pressure regulation in humans.…”

Cerebrovascular Smooth Muscle Reactivity: A Critical Appraisal of in vitro and in situ Techniques

“…Values of maximum responses and EC50 are derived from data of Kuschinsky et al (1974) and Edvinsson et a\. (1977Edvinsson et a\. ( , 1982; Larsson et al (1976); McCulloch and Edvinsson (1980); Hanko and Hardebo (1978); Wahl et al (1974Wahl et al ( , 1983; Edvinsson and Owman (1974); Edvinsson et a\.…”