Dopamine-?-hydroxylase-, neurotensin-, substance P-, vasoactive intestinal polypeptide- and enkephalin-immunohistochemistry of paravertebral and prevertebral ganglia in the cat

Abstract

Para and prevertebral ganglia of the cat were investigated for immunoreactivity (IR) against neurotensin (NT), vasoactive intestinal polypeptide (VIP), substance P (SP) and enkephalin (ENK). Dopamine-β-hydroxylase- (DBH)-IR was studied in consecutive sections to correlate the distribution of noradrenergic/adrenergic neurons with that of peptidergic nerve fibres and cells. In paravertebral (cervical and thoracic) ganglia, NT-IR or ENK-IR nerve fibres were seen in areas in which DBH-IR fibre networks also occurred. NT-IR varicosities were often in close contact with perikarya of principal ganglionic cells on which DBH-IR varicosities also terminated. Such an association was rarely seen between ENK-IR and DBH-IR fibre baskets. NT-IR and ENK-IR fibre baskets were not found to occur around the same principal ganglionic cell. The distribution of VIP-IR and SP-IR nerve fibres did not coincide with that of DBH-IR fibres. In prevertebral ganglia (celiac-superior mesenteric and inferior mesenteric) DBH-IR or VIP-IR varicosities surrounded the majority of principal ganglionic neurons. ENK-IR or SP-IR fibres were closely associated with only a minority of the neurons; NT-IR networks were rather sparse. Some principal neurons were approached by DBH-IR fibres and by different peptide-IR fibres. In paravertebral ganglia some principal ganglionic cells contained VIP-IR, a few of which were also surrounded by NT-IR varicosities. VIP-IR perikarya in prevertebral ganglia were extremely rare. No NT-IR, SP-IR or ENK-IR principal ganglionic cells were found. Glomus-like paraganglionic cell clusters in paravertebral and prevertebral ganglia exhibited DBH-IR cell bodies. Moreover, the clusters also contained ENK-IR or SP-IR cells. NT-IR varicosities were observed adjacent to clustered paraganglionic cells. Only few singly located paraganglionic cells were NT-IR or ENK-IR. The differential distribution of peptide-IR nerve endings in the investigated ganglia suggests a regulation of impulse transmission that seems to be related to the target organs.