Comparative study on the innervation of nerves with calcitonin gene-related peptide, substance P and neurokinin A immunoreactivity in the walls of the cerebral arteries of small bats (Mammalia: Microchiroptera).
The distribution and origin of nerves with calcitonin gene-related peptide, substance P or neurokinin A immunoreactivity in the walls of the cerebral arteries were investigated in three microchiropteran species. The supply of nerves immunoreactive for substance P and neurokinin A to the bat cerebral arteries is confined mostly to the vertebral and basilar arteries. The density of innervation of calcitonin gene-related peptide-immunoreactive nerves and that of nerves with substance P or neurokinin A immunoreactivity in the vertebrobasilar system differ among species: the Japanese large footed bat is innervated with nerves with calcitonin gene-related peptide, substance P and neurokinin A immunoreactivity with about the same density, whereas in the greater horseshoe bat, there are many substance P-immunoreactive nerves with very weak or no calcitonin gene-related peptide immunoreactivity, and in the bent-winged bat, calcitonin gene-related peptide immunoreactivity is not found in all nerves with substance P immunoreactivity in the pial arteries of all parts of the brain. Nearly all cells immunoreactive for substance P, calcitonin gene-related peptide or both in the trigeminal and cervical dorsal root ganglia were small. In the greater horseshoe bat and the bent-winged bat, there is a correlation between the level of expression of substance P and calcitonin gene-related peptide immunoreactivity in the cervical dorsal root and trigeminal ganglia and the cerebral perivascular nerves supplying the vertebrobasilar system. The cerebrovascular innervation of nerves with substance P immunoreactivity in small bats is similar to that of cats and guinea-pigs in which the trigeminal ganglia have been destroyed. These observations, in addition to absence of nerve cells showing substance P or calcitonin gene-related peptide immunoreactivity in the pial artery and in the nerve bundles accompanying the extracranial internal carotid and vertebral arteries, suggest that substance P-immunoreactive nerves with or without immunoreactivity to calcitonin gene-related peptide in the vertebrobasilar system of small bats originate exclusively from the cervical dorsal root ganglia. The remaining fibres probably originate in the trigeminal ganglia.
Biological Laboratory, Liberal Arts, Kyushu Sangyo University, Fukuoka, Japan.
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Ando
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Arai
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Kawamura
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000502:physiology*; D002536:Cerebral Arteries / Q000294:innervation*; D002685:Chiroptera / Q000502:physiology*; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D015288:Neurokinin A / Q000502:physiology*; D009475:Neurons, Afferent / Q000201:enzymology; D013045:Species Specificity; D013194:Staining and Labeling; D013373:Substance P / Q000502:physiology*
D013373:Substance P; D015288:Neurokinin A; D000110:Acetylcholinesterase; D015740:Calcitonin Gene-Related Peptide