Naokuni Takeda

Phylogenetic detection of serotonin immunoreactive cells in the central nervous system of invertebrates

Abstract 1. The localization of serotonin (5-hydroxytryptamine) immunoreactive cells was examined phylogenetically in the central nervous system of invertebrates. 2. Invertebrate species used were as follows: Hydra magnipapillata of Coelenterata, Bipalium sp. of Platyhelminthes, Neanthes japonica and Pheretima communissima of Annelida, Ligia exotica, Procambarus clarkii. Helice tridens and Gryllus bimaculatus of Arthropoda, Pomacea canaliculata, Aplysia kurodai, Achatina fulica and Limax marginatus of Mollusca, Asterina pectinifera of Echinodermata and Halocynthia roretzi of Protochordata. 3. Serotonin immunoreactivity was recognized in the central nervous system of most of these species. However, the immunoreactivity was unclear in Hydra, Asterina and Halocynthia . The distribution of positive cells became centralized in the central nervous system of A. kurodai, A.fulica and L. marginatus . 4. Serotonin cells in the central nervous system of invertebrates were suggested to have a tendency to aggregate and finally to centralize with the phylogenetical progress of the species.

Hormonal control of prepupal diapause in Monema flavescens (Lepidoptera)

Abstract Injection of β-ecdysone into the abdomen of diapausing prepupae of Monema flavescens induced an extra ecdysis, resulting in prepupal-pupal intermediates instead of normal pupae. If diapausing prepupae were allatectomized, diapause soon broke and pupation took place frequently. Implantation of corpora allata from diapausing donors into early post-diapause or allatectomized prepupae induced diapause again in the hosts. Hemolymph levels of juvenile hormone rose during early diapause period and fell gradually toward the end of diapause. Changes in volume of corpora allata occurred in parallel to rise and fall in hemolymph level of juvenile hormone. Brains from diapausing prepupae implanted into decapitated diapausing prepupae caused pupation in the hosts within a short period. By contrast, implantation of brain-corpora allata complexes from diapausing prepupae did not result in quick pupation of the recipients. Implantation of corpora allata into diapausing prepupae gave rise to a significant decrease in nuclear volume in neurosecretory B cells in the pars intercerebralis, while extirpation of corpora allata resulted in a significant increase. The increase in nuclear volume following allatectomy was suppressed by implantation of corpora allata from diapausing donors. Prepupal diapause in Monema flavescens seems to be initiated and maintained by an inhibitory action of juvenile hormone on the release of neurosecretory materials from B cells of the pars intercerebralis. When the period of active secretion of corpora allata comes to an end, the brain-prothoracic gland system is activated and diapause is broken.

Phylogenetic study of the arginine-vasotocin/arginine-vasopressin-like immunoreactive system in invertebrates

1. A phylogenetic study of arg-vasotocin (AVT)/arg-vasopressin (AVP)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata; Neanthes japonica and Pheretima communissima of the Annelida; Pomacea canaliculata, Aplysia kurodai, Oncidium verrucosum, Bradybaena similaris, Achatina fulica, Limax marginatus and Meretrix lamarckii of the Mollusca; Gnorimosphaeroma rayi, Hemigrapsus sanguineus, Gryllus bimaculatus and Baratha brassicae of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 3. No immunoreactivity was detected in Bipalium sp. of the Platyhelminthes, or in Procambarus clarkii and Helice tridens of the Arthropoda. 4. From these results, it appears that AVT/AVP is a phylogenetically ancient peptide which is present in a wide variety of invertebrates. 5. The actions of AVT/AVP and its presence in invertebrates are discussed.

Phylogenetic study of the oxytocin-like immunoreactive system in invertebrates

1. A phylogenetic study of oxytocin (OXT)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata; Neanthes japonica and Pheretima communissima of the Annelida; Oncidium verrucosum, Limax marginatus and Meretrix lamarckii of the Mollusca; and Baratha brassica of the Arthropoda. 3. No immunoreactive cells were found in Bipalium sp. of the Platyhelminthes; Pomacea canaliculata, Aplysia kurodai, Bradybaena similaris and Achatina fulica of the Mollusca; and Gnorimosphaeroma rayi, Procambarus clarkii, Hemigrapsus sanguineus, Helice tridens and Gryllus bimaculatus of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 4. These results demonstrate that an OXT-immunoreactive substance is widely present not only in vertebrates but also in invertebrates. 5. OXT seems to have been introduced into these invertebrates at an early stage of their phylogenetic history.

Biogenic monoamine levels in the central nervous system of the sea hare, Aplysia kurodai

Abstract 1. By using a three-dimensional-coulometric HPLC system, biogenic monoamines and their metabolites were quantified simultaneously in the central nervous system of the sea hare, Aplysia kurodai. 2. Precursor amino acids, tyrosine-4 (TYR-4) and tryptophan (TRP), and dopamine (DA), 3, 4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxytryptamine (5-HT) were detected in all the ganglia examined. 3. Levels of these compounds in the cerebral, pedal and parieto-visceral ganglia were higher than those of the other ganglia examined. 4. In some ganglia, epinephrine (E), 3-O-methyldopa (30MD), 3-methoxytyramine (3-MT), dihydroxyphenylethleneglycol (DOPEG), metanephrine (MN), vanillic acid (VA), octopamine (OCT), kynurenine (KYN) and 5-hydroxyindoleacetic acid (5-HIAA) were also detected. 5. The main metabolic pathways of biogenic monoamines were shown to be TYR-4DADOPAC and TRP5-HT5-HIAA. Furthermore, following five pathways were also suggested to be present; TYR-4DAEMNVA, TYR-4TYRAOCT, TYR-43OMD, DA3-MT. EDOPEG and TRPKYN.

Hormonal Control of Gametogenesis in the Terrestrial Snail, Euhadra peliomphala

Effects of the cerebral ganglion (brain) and the optic gland on oogenesis and spermatogenesis were studied in the terrestrial snail, Euhadra peliomphula. Removal of the optic tentacles inhibited both oogenesis and spermatogenesis. These effects were abolished by the injection of the optic tentacle extract. In the tissue of the optic tentacle, only the optic gland showed the recovery action. Furthermore, in vitro the optic gland extract stimulated spermatogenesis but had no effect on oogenesis. On the contrary, the brain extract promoted oogenesis not only in vitro and but also in viva The hermaphroditic gland extract reduced the nuclear volume of the optic gland cells, but the brain extract did not. In addition, among sex steroid hormones secreted from the hermaphroditic gland, only testosterone also reduced the nuclear volume of optic gland cells. On the basis of these results, hormonal mechanisms of gametogenesis in Euhadra peliomphala are discussed.

Brain hormone carrier haemocytes in the moth Monema flavescens

Abstract The movement of neurosecretory substances released from the neurosecretory B cell in the pars intercerebralis to the haemolymph was examined with the progress of the termination of diapause in the slug moth pharate pupa, Monema flavescens. The injection of precipitates in the haemolymph of the pharate pupa just before the termination of diapause into diapausing pharate pupae reduced the numbers of days required for them to pupate. In the precipitates, seven types of haemocytes were present. The number of haemocytes, especially the granular cell, increased just before the termination of diapause. AF and CHP positive substances not detected in the haemocytes of diapausing pharate pupae appeared in the granular cells just before the termination of diapause. The period also coincided well with the releasing period of the neurosecretory B cell. Histological examination showed that granular haemocytes gathered around the pars intercerebralis at this period and exchange of neurosecretory substances occurred between granular haemocytes and neurosecretory B cells. Then granular haemocytes migrated to the region of the prothoracic gland. From digestion tests of the neurosecretory substances with rabbit serum and from the implantation tests of the neuroendocrine system, the substances detected in both the neurosecretory B cell and the granular haemocytes seemed to be the same. The dye injection caused a delay in larval-pupal ecdysis emergence. Droplets of black ink are incorporated into the granular haemocytes. This seems to be caused by blocking of the transport of neurosecretory substances released from cytoplasmic processes of the neurosecretory B cell. From these experiments, it is suggested that neurosecretory substances of the prothoracotropic hormone are transported to the prothoracic gland, along with granular haemocytes, after being released directly from the neurosecretory B cell to the haemolymph.

Evidence for neurosecretory control of the optic gland in terrestrial pulmonates

The optic gland in terrestrial pulmonates secretes gonadotropic hormone. The present study investigates the fine structure of the optic gland to clarify the control of secretion. Animals used were the slug, Limax marginatus, and the snail, Euhadra peliomphala. The optic gland cell has a process and the cytoplasm is filled with large granules about 750-1300 nm in diameter with a thin cortex in L. marginatus and 800-1700 nm delimited by a thick peripheral layer in E. peliomphala. These gland cells are characterized by well-developed granular endoplasmic reticulum. Granule formation was seen in the region of the Golgi apparatus. During the breeding season, the medial neurosecretory cells of the brain are active in the production and release of secretory materials. Although no neurosecretory cell bodies occur in the tentacular ganglion, neurosecretory axons penetrate into the optic gland cells. Cobalt filling reveals that axons of the medial neurosecretory cells project to the tentacular ganglion, near the optic gland. These results suggest that the optic gland is controlled by a neurohormone originating from the medial neurosecretory cells of the brain.

Neuroendocrine control of the dorsal bodies in the giant African snail, Achatina fulica

Summary In the giant African snail, Achatina fulica, the ultrastructure of the dorsal bodies was examined in an attempt to characterize the neural control of their activity. In the dorsal body many large ellipsoidal lipid droplets with a thick electron-dense cortex and secretory granules with an electron-dense core were found. In a bundle of commissural nerves that originated from the cerebral ganglion, two types of axon were detected: type I axons contained spherical granules and type II axons contained ellipsoidal granules. These axons innervated the dorsal body cells. Our results suggest that each cell of the dorsal bodies is under the control of two axons from the cerebral ganglion: one that is stimulatory and another that may be inhibitory.

Simultaneous analyses of monoamines and their metabolites in urine specimens of patients with neuroblastoma

1. Tyrosine and tryptophan, as well as 26 metabolites of these amino acids, were analyzed simultaneously in urine specimens from patients with neuroblastoma and control infants by a three-dimensional HPLC system to develop an early diagnosis. 2. Levels of detected compounds in urine from patients with neuroblastoma were generally higher in the case of catecholamines and lower in the case of indolalkylamines than those in controls. 3. The pathways of Dopamine-3,4-Dihydroxyphenylacetic acid-Vanillylmandelic acid, Dopamine-3-Methoxy-4-hydroxyphenylethylene glycol-Vanillylmandelic acid and Tyrosine-4-Hydroxyphenylacetic acid-4 were, in particular, found to be active in patients with neuroblastoma.