The Neurosecretory Cells of the Brain of Aedes aegypti in Relation to Larval Molt, Metamorphosis and Ovarian Development

1968 ◽  
Vol 87 (4) ◽  
pp. 395 ◽  
Author(s):  
Joseph R. Larsen ◽  
Alan Broadbent
1979 ◽  
Vol 205 (1160) ◽  
pp. 411-421 ◽  

Most female mosquitoes require a blood-meal in order to produce mature oöcytes. An egg development neurosecretory hormone (EDNH), which is produced in the medial neurosecretory cells (m. n. c.) of the brain and stored in the corpus cardiacum, is released into the haemolymph following the ingestion of blood and is essential for the promotion of ovarian development to maturity. It has been shown that a factor from the m. n. c., presumably EDNH, is necessary if the blood-meal is to be retained in the mid-gut until the oöcytes approach maturity. The present paper shows that retention is not a direct result of the action of EDNH, but is dependent on the ovaries and may well involve ecdysone. Removal of the ovaries before a blood-meal leads to early haem-defaecation, but delay can be restored by injection of ecdysterone. Sub-threshold feeders and mosquitoes decapitated immediately after the intake of blood, each of which would be expected to eliminate the blood-meal early, also show a delay in the onset of haem-defaecation when injected with ecdysterone. Further, both in ovariectomized insects and sub-threshold feeders the time of onset of haem-defaecation is associated with the dose of ecdysterone given.


1978 ◽  
Vol 202 (1147) ◽  
pp. 307-311 ◽  

Development of the oöcytes beyond the resting stage to maturity in mosquitoes is triggered by an egg development neurosecretory hormone from the brain. This hormone is produced by the medial neurosecretory cells of the pars intercerebralis, and in anautogenous species is stored in the corpus cardiacum until a blood-meal is taken. Removal of the head of the mosquito Aedes aegypti (L.), shortly after completion of a blood-meal, has previously been shown not only to prevent oöcyte maturation, but also to result in early elimination of the blood-meal. The work described in this paper shows that it is a factor originating in the medial neuro­-secretory cells, presumably egg development neurosecretory hormone, which is essential if the blood-meal is to be retained in the mid-gut until the oöcytes are nearing maturity.


Author(s):  
M. Sato ◽  
Y. Ogawa ◽  
M. Sasaki ◽  
T. Matsuo

A virgin female of the noctuid moth, a kind of noctuidae that eats cucumis, etc. performs calling at a fixed time of each day, depending on the length of a day. The photoreceptors that induce this calling are located around the neurosecretory cells (NSC) in the central portion of the protocerebrum. Besides, it is considered that the female’s biological clock is located also in the cerebral lobe. In order to elucidate the calling and the function of the biological clock, it is necessary to clarify the basic structure of the brain. The observation results of 12 or 30 day-old noctuid moths showed that their brains are basically composed of an outer and an inner portion-neural lamella (about 2.5 μm) of collagen fibril and perineurium cells. Furthermore, nerve cells surround the cerebral lobes, in which NSCs, mushroom bodies, and central nerve cells, etc. are observed. The NSCs are large-sized (20 to 30 μm dia.) cells, which are located in the pons intercerebralis of the head section and at the rear of the mushroom body (two each on the right and left). Furthermore, the cells were classified into two types: one having many free ribosoms 15 to 20 nm in dia. and the other having granules 150 to 350 nm in dia. (Fig. 1).


2017 ◽  
Vol 23 (1) ◽  
Author(s):  
C.A. JAWALE

Ovarian maturation by neurosecretory cells in the brain of freshwater crab, Barytelphusa cunicularis have been examined. The histological scrutiny of the brain of Barytelphusa cunicularis related with three types (A, B and C) of neurosecretory cells, which are classified on the basis of size, shape and tinctorial characters. All these types of cells marked annual cyclic changes of cytoplasmic material in association with ovarian cycle. The activity of these cells has been correlated with the ovarian cycle. They are distinguishable by their size, nature locations, shape, nucleus position, cell measure and the secretory product in the cytoplasm. The result indicates that the neurosecretory A, B and C cells of the brain seen involved in the process of mating ovulation. The neurosecretory materials staining intensity index of these cells is described.


Nature ◽  
1957 ◽  
Vol 179 (4553) ◽  
pp. 257-258 ◽  
Author(s):  
ALASTAIR FRASER

2019 ◽  
Author(s):  
Dick R Nässel ◽  
Dennis Pauls ◽  
Wolf Huetteroth

Neuropeptides constitute a large and diverse class of signaling molecules that are produced by many types of neurons, neurosecretory cells, endocrines and other cells. Many neuropeptides display pleiotropic actions either as neuromodulators, co-transmitters or circulating hormones, while some play these roles concurrently. Here, we highlight pleiotropic functions of neuropeptides and different levels of neuropeptide signaling in the brain, from context-dependent orchestrating signaling by higher order neurons, to local executive modulation in specific circuits. Additionally, orchestrating neurons receive peptidergic signals from neurons conveying organismal internal state cues and relay these to executive circuits. We exemplify these levels of signaling with four neuropeptides, SIFamide, short neuropeptide F, allatostatin-A and leucokinin, each with a specific expression pattern and level of complexity in signaling.


1959 ◽  
Vol s3-100 (51) ◽  
pp. 377-394
Author(s):  
ALASTAIR FRASER

Six groups of neurosecretory cells were identified in the brain of the mature larva of Lucilia caesar. Five of these groups belonged to the category of medial neurosecretory cells and one to that of lateral neurosecretory cells. The groups differ in position, cell size, staining characteristics, and sequence of activity. It is apparent that only some of the groups are concerned with the process of thoracic gland activation, though all function during metamorphosis. At least one group, not concerned in thoracic gland activation in the non-diapause larva, is continually active during diapause.


1964 ◽  
Vol 96 (1-2) ◽  
pp. 105-106 ◽  
Author(s):  
L. Burgess ◽  
J. G. Rempel

This exhibit represents some portions of a study of the stomodaeal nervous system, neurosecretory cells, corpora allata, corpora cardiaca, and prothoracic gland cells in post-embryonic stages of Aedes aegypti (L.), the yellow fever mosquito. Some of these structures share the common property of being involved in the production of hormones.Mosquitoes were reared under standard conditions. Larvae, pupae and adults were fixed at timed intervals in histological fixatives. Sectioned specimens were stained in Gomori's aldehyde-fuchsin, Gomori's chrome-haematoxyh-phloxin and other stains. The aldehyde-fuchsin technique, which imparted a bright purple colour to neurosecretory material, was particularly useful. Vita1 staining with methylene blue was used to trace the stomodaeal nervous system


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