椎骨動脈周囲の神経組織—特にPacini小体の分布について

The pacinian corpuscles around the vertebral artery

I．いとぐち

　人間の脳の主として前半は頸動脈系にて血液を供給されているが，生命に直接関係のある諸中枢の多い後半は椎骨動脈系によって血液を供給されている。頸動脈系では血圧の変動に対する受容器，また血液の化学的性状の変化に対する受容器については以前より広く究明されているが^1）2），同じく脳へ血流を送り，しかも延髄をはじめ諸中枢の多い脳の後半に関係する椎骨動脈系に，そのように分化した受容器の認められないのはむしろ不思議に思われる。

　頸動脈系と椎骨動脈系とでは，種々の条件において循環状態を異にすることは知られており実験的にも示されている^3）。

Recently a congromelate of the epitheloid, paraganglion-like cells, named" the Syphon Body", was discovered at the site through which the internal carotid artery enters into the cranial cavity and was reported to play a roll in regulating the cerebral circulation. As to the vertebral artery system which supplys blood to the posterior part of the other hand, it has been certainly curious for me that no receptors like the carotid body nor" the Syphon Body" along the carotid ar-tery has yet been reported. This was my main motives for starting this research.

The material consisted of the 26 vertebral arteries with the surrounding tissues dissected from the human cadavers and was studied microscopically after serial sectioning. The specimens containing the osseous tissue were decalcified by means of electrolysis.

The unexpectingly numerous-12 to 37 paci-nian corpuscles were found in the loose con-nective tissue around the each vertebral artery. Most of these corpuscles were noticed along the cranial third of the artery which presents a curious curvature before entering the cranium. These corpuscles were seldom situated directly on the adventitia of the artery but mainly found in the loose connec-tive tissue aparting from the arterial wall itself.

The pacinian corpuscle has been considered to play a roll not only as a nerve ending for deep sensation but also for circulatory adjustment. The corpuscles surrounding the artery have been so far reported to be noti-ced only along the abdominal aorta and some confined part of the femoral artery.

Accumulation of the numerous pacinian corpuscles in the closed space like that in the costtransversal foramina of the upper cervi-cal spines is highly suggestive for posibility of having something to do with regulating circulation through the vertebral artery.