Distribution of FMRFamide-like immunoreactivity in the brain and neurohypophysis of the lamprey, Lampetra japonica.
Distribution of molluscan cardio-excitatory tetrapeptide Phe-Met-Arg-Phe-NH2 (FMRFamide) was determined by means of immunohistochemistry in the brain and neurohypophysis of the lamprey, Lampetra japonica. Many FMRFamide-like immunoreactive neurons were found in the periventricular nuclear region and in a region near the mammillary recess. Neurons situated in the former region were larger. The immunoreactive cell groups were shown to be located at sites differing from those of the AF-positive cell groups. The fibers of immunoreactive neurons extended in all directions within the brain and towards the spinal cord, some reaching the third ventricle and capillaries. Thus, FMRFamide-like immunoreactive peptides appear to function as neurotransmitters or neuromodulators and possibly also as neurohormones. FMRFamide-like immunoreactive material was rarely observed in the posterior neurohypophysis (neural lobe), but was noted to be present to a limited extent in the caudal part of the anterior neurohypophysis (median eminence). It would thus follow that FMRFamide-like immunoreactive neurons may not necessarily be related to the hypothalamo-neural lobe system, but may possibly be associated with the hypothalamo-adenohypophysial system. The pineal body showed no FMRFamide-like immunoreactivity.
Ohtomi
M
M
Department of Chemistry, Faculty of Science, Toho University, Chiba, Japan.
Fujii
K
K
Kobayashi
H
H
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D019835:FMRFamide; D005399:Fishes / Q000378:metabolism*; D007150:Immunohistochemistry; D007798:Lampreys / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000166:cytology / Q000378:metabolism*
D009479:Neuropeptides; D019835:FMRFamide