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Expression and distribution of CB1 cannabinoid receptors in the central nervous system of the African cichlid fish Pelvicachromis pulcher
Author(s) -
Cottone Erika,
Forno Sarah,
Campantico Ezio,
Guastalla Alda,
Viltono Laura,
Mackie Ken,
Franzoni Maria Fosca
Publication year - 2005
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20502
Subject(s) - biology , tegmentum , pretectal area , diencephalon , cerebrum , midbrain , cerebellum , brainstem , anatomy , spinal cord , cichlid , cannabinoid receptor , central nervous system , neuroscience , receptor , agonist , biochemistry , fishery , fish <actinopterygii>
Neuroanatomical investigation of the cannabinoid system in a lower vertebrate group such as teleost fishes might improve our understanding of the physiological role of such a signaling system. In the present study, the expression of a CB1 cannabinoid receptor has been demonstrated in the CNS of a teleost fish, the cichlid Pelvicachromis pulcher . Moreover, CB1‐like immunoreactivity has been analyzed by using a purified antibody against the CB1 receptor amino‐terminus. Immunostained neurons and varicosities were found through the telencephalon as well as in the preoptic area and lateral infundibular lobes of the hypothalamus. Stained cells were observed in the pituitary gland. Several cell bodies and nerve terminals containing an intense CB1‐like immunoreactivity were found in the pretectal central nucleus and posterior tuberculum, both lying in a transitional region between diencephalon and mesencephalon. In the brainstem, the CB1 immunopositivity was more restricted than in the prosencephalon, with the exception of some large, intensely immunopositive nerve cells within the dorsal mesencephalic tegmentum, possibly motor neurons of the third cranial nerve. In the cerebellum, among a majority of immunonegative granule cells, a subset of them was immunostained. Some positive Purkinje cells were also observed. In the spinal cord, ventral gray matter, several α‐motoneurons were stained. Similarities to and discrepancies from the CB1 receptor distributions in other vertebrate CNS are discussed, paying particular attention to the abundant CB1 immunoreactivity observed in the area encompassing the pretectum and glomerular nucleus, which is characterized by a peculiar differentiation in bony fishes. J. Comp. Neurol. 485:293–303, 2005. © 2005 Wiley‐Liss, Inc.