Cholecystokinin in the central nervous system of the sea lamprey Petromyzon marinus: precursor identification and neuroanatomical relationships with other neuronal signalling systems.
Brain Struct Funct
; 225(1): 249-284, 2020 Jan.
Article
en En
| MEDLINE
| ID: mdl-31807925
ABSTRACT
Cholecystokinin (CCK) is a neuropeptide that modulates processes such as digestion, satiety, and anxiety. CCK-type peptides have been characterized in jawed vertebrates and invertebrates, but little is known about CCK-type signalling in the most ancient group of vertebrates, the agnathans. Here, we have cloned and sequenced a cDNA encoding a sea lamprey (Petromyzon marinus L.) CCK-type precursor (PmCCK), which contains a CCK-type octapeptide sequence (PmCCK-8) that is highly similar to gnathostome CCKs. Using mRNA in situ hybridization, the distribution of PmCCK-expressing neurons was mapped in the CNS of P. marinus. This revealed PmCCK-expressing neurons in the hypothalamus, posterior tubercle, prethalamus, nucleus of the medial longitudinal fasciculus, midbrain tegmentum, isthmus, rhombencephalic reticular formation, and the putative nucleus of the solitary tract. Some PmCCK-expressing neuronal populations were only observed in adults, revealing important differences with larvae. We generated an antiserum to PmCCK-8 to enable immunohistochemical analysis of CCK expression, which revealed that GABA or glutamate, but not serotonin, tyrosine hydroxylase or neuropeptide Y, is co-expressed in some PmCCK-8-immunoreactive (ir) neurons. Importantly, this is the first demonstration of co-localization of GABA and CCK in neurons of a non-mammalian vertebrate. We also characterized extensive cholecystokinergic fibre systems of the CNS, including innervation of habenular subnuclei. A conspicuous PmCCK-8-ir tract ascending in the lateral rhombencephalon selectively innervates a glutamatergic population in the dorsal isthmic grey. Interestingly, this tract is reminiscent of the secondary gustatory/visceral tract of teleosts. In conclusion, this study provides important new information on the evolution of the cholecystokinergic system in vertebrates.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Precursores de Proteínas
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Encéfalo
/
Colecistoquinina
/
Petromyzon
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Neuronas
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Brain Struct Funct
Asunto de la revista:
CEREBRO
Año:
2020
Tipo del documento:
Article
País de afiliación:
España