Eclosion hormone-stimulated cGMP levels in the central nervous system of Manduca sexta: inhibition by lipid metabolism blockers, increase in inositol(1,4,5)trisphosphate and further evidence against the involvement of nitric oxide

1995 ◽  
Vol 165 (6) ◽  
Author(s):  
D.B. Morton ◽  
P.J. Simpson
Keyword(s):  
Nitric Oxide ◽  
Central Nervous System ◽  
Nervous System ◽  
Lipid Metabolism ◽  
Manduca Sexta ◽  
Eclosion Hormone ◽  
Inositol 1,4,5 Trisphosphate ◽  
The Central Nervous System

The Larval Eclosion Hormone Neurones in Manduca Sexta: Identification of the Brain-Proctodeal Neurosecretory System

1989 ◽  
Vol 147 (1) ◽  
pp. 457-470 ◽  
Author(s):  
JAMES W. TRUMAN ◽  
PHILIP F. COPENHAVER
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Nerve Cord ◽  
Release Site ◽  
Neurosecretory System ◽  
Nerve Activity ◽  
Eclosion Hormone ◽  
The Central Nervous System ◽  
The Brain

Larval and pupal ecdyses of the moth Manduca sexta are triggered by eclosion hormone (EH) released from the ventral nervous system. The major store of EH activity in the latter resides in the proctodeal nerves that extend along the larval hindgut. At pupal ecdysis, the proctodeal nerves show a 90% depletion of stored activity, suggesting that they are the major release site for the circulating EH that causes ecdysis. Surgical experiments involving the transection of the nerve cord or removal of parts of the brain showed that the proctodeal nerve activity originates from the brain. Retrograde and anterograde cobalt fills and immunocytochemistry using antibodies against EH revealed two pairs of neurons that reside in the ventromedial region of the brain and whose axons travel ipsilaterally along the length of the central nervous system (CNS) and project into the proctodeal nerve, where they show varicose release sites. These neurons constitute a novel neuroendocrine pathway in insects which appears to be dedicated solely to the release of EH.

Excitatory and inhibitory roles of central ganglia in initiation of the insect ecdysis behavioural sequence

2000 ◽  
Vol 203 (8) ◽  
pp. 1329-1340 ◽  
Author(s):  
D. Zitnan ◽  
M.E. Adams
Keyword(s):  
Neural Network ◽  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Abdominal Ganglion ◽  
Suboesophageal Ganglion ◽  
Eclosion Hormone ◽  
The Central Nervous System ◽  
Inka Cells ◽  
Behavioural Sequence

Insects shed their old cuticle by performing the ecdysis behavioural sequence. To activate each subunit of this set of programmed behaviours in Manduca sexta, specific central ganglia are targeted by pre-ecdysis-triggering (PETH) and ecdysis-triggering (ETH) hormones secreted from Inka cells. PETH and ETH act on each abdominal ganglion to initiate, within a few minutes, pre-ecdysis I and II, respectively. Shortly thereafter, ETH targets the tritocerebrum and suboesophageal ganglion to activate the ecdysis neural network in abdominal ganglia through the elevation of cyclic GMP (cGMP) levels. However, the onset of ecdysis behaviour is delayed by inhibitory factor(s) from the cephalic and thoracic ganglia. The switch from pre-ecdysis to ecdysis is controlled by an independent clock in each abdominal ganglion and is considerably accelerated after removal of the head and thorax. Eclosion hormone (EH) appears to be one of the central signals inducing elevation of cGMP levels and ecdysis, but these actions are quite variable and usually restricted to anterior ganglia. EH treatment of desheathed ganglia also elicits strong production of cGMP in intact ganglia, suggesting that this induction occurs via the release of additional downstream factors. Our data suggest that the initiation of pre-ecdysis and the transition to ecdysis are regulated by stimulatory and inhibitory factors released within the central nervous system after the initial actions of PETH and ETH.

scholarly journals The initiation of pre-ecdysis and ecdysis behaviors in larval Manduca sexta: the roles of the brain, terminal ganglion and eclosion hormone.

1996 ◽  
Vol 199 (8) ◽  
pp. 1757-1769 ◽  
Author(s):  
A Novicki ◽  
J C Weeks
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Brain Neurons ◽  
Eclosion Hormone ◽  
Terminal Ganglion ◽  
The Central Nervous System ◽  
Time Required ◽  
The Brain ◽  
Larval Molt

Each larval molt of Manduca sexta culminates in the sequential performance of pre-ecdysis (cuticle loosening) and ecdysis (cuticle shedding) behaviors. Both behaviors are thought to be triggered by the release of a peptide, eclosion hormone (EH), from brain neurons whose axons extend the length of the nervous system. EH bioactivity appears in the hemolymph at the onset of pre-ecdysis behavior, and EH injection can trigger pre-ecdysis and ecdysis behaviors prematurely. The present study examined the effects of removing or disconnecting portions of the central nervous system prior to the time of EH release on the initiation of pre-ecdysis and ecdysis behaviors at the final larval molt. We found that the initiation of pre-ecdysis abdominal compressions at the appropriate time required the terminal abdominal ganglion (AT) but not the brain; the initiation of pre-ecdysis proleg retractions at the appropriate time required neither the AT nor the brain; the initiation of ecdysis at the appropriate time usually required the brain but did not require the AT; and premature pre-ecdysis (but not ecdysis) could be elicited in isolated abdomens by injection of EH. Finally, pre-ecdysis behavior performed by brainless larvae was not associated with the normal elevation of EH bioactivity in the hemolymph or the normal loss of EH immunoreactivity from peripheral neurohemal release sites.

Abstract 103: ACE2 Overexpression Prevents DOCA-Salt Hypertension by Modulating Oxidative Stress and Nitric Oxide in the Central Nervous System

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Srinivas Sriramula ◽  
Huijing Xia ◽  
Eric Lazartigues
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Central Nervous System ◽  
Nervous System ◽  
Nadph Oxidase ◽  
Salt Treatment ◽  
Salt Hypertension ◽  
The Central Nervous System ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Elevated reactive oxygen species (ROS) in the central nervous system (CNS) through NADPH oxidase and diminished Nitric oxide (NO) levels are involved in the pathogenesis of hypertension. We previously reported that central Angiotensin Converting Enzyme 2 (ACE2) overexpression prevents the development of hypertension induced by DOCA-salt in a transgenic mouse model (syn-hACE2; SA) with human ACE2 targeted selectively to neurons in the CNS. While baseline blood pressure (BP; telemetry) was not different among genotypes, DOCA-salt treatment (1mg/g body wt DOCA, 1% saline in drinking water for 3 weeks) resulted in significantly lower BP level in SA mice (122 ±3 mmHg, n=12) compared to non-transgenic (NT) littermates (138 ±3 mmHg, n=8). To elucidate the mechanisms involved in this response, we investigated the paraventricular nucleus (PVN) expression of Nox-2 (catalytic subunit of NADPH oxidase), 3-nitrotyrosine, and endothelial nitric oxide synthase (eNOS) and anti-oxidant enzymes superoxide dismutase (SOD) and catalase in the hypothalamus. DOCA-salt treatment resulted in decreased catalase (95.2 ±5.6 vs. 113.8 ±17.6 mmol/min/ml, p<0.05) and SOD (4.1 ±0.4 vs. 5.9 ±0.2 U/ml, p<0.01) activities in hypothalamic homogenates of NT mice, which was prevented by ACE2 overexpression (141.8 ±9.9 vs. 142.1 ±9.2 mmol/min/ml and 5.9 ±0.3 vs. 7.9 ±0.2 U/ml, respectively). NT mice treated with DOCA-salt showed increased oxidative stress as indicated by increased expression of Nox-2 (61 ±5 % increase, n=9, p<0.001 vs. NT) and 3-nitrotyrosine (89 ±32 % increase, n=9, p<0.01 vs. NT) in the PVN which was attenuated in SA mice. Furthermore, DOCA-salt hypertension resulted in decreased phosphorylation of eNOS-ser1177 in the PVN (33 ±5 % decrease, n=9, p<0.05 vs NT) and this decrease was prevented by ACE2 overexpression. Taken together, these data provide evidence that brain ACE2 regulates the balance between NO and ROS levels, thereby preventing the development of DOCA-salt hypertension.

Adipokinetic hormone stimulates neurones in the insect central nervous system.

1995 ◽  
Vol 198 (6) ◽  
pp. 1307-1311
Author(s):  
J J Milde ◽  
R Ziegler ◽  
M Wallstein
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Central Action ◽  
Adipokinetic Hormone ◽  
Metabolic Functions ◽  
Simple Preparation ◽  
Pressure Injection ◽  
The Central Nervous System ◽  
Insect Central Nervous System

A simple preparation designed to screen and compare the central action of putative neuroactive agents in the moth Manduca sexta is described. This approach combines microinjections into the central nervous system with myograms recorded from a pair of spontaneously active mesothoracic muscles. Pressure injection of either octopamine or Manduca adipokinetic hormone (M-AKH) into the mesothoracic neuropile increases the monitored motor activity. Under the conditions used, the excitatory effects of M-AKH exceed those of the potent neuromodulator octopamine. This suggests that M-AKH plays a role in the central nervous system in addition to its known metabolic functions and supports recent evidence that neuropeptides in insects can be multifunctional.

scholarly journals Drugs modulating the L-arginine:NO:cGMP pathway – current use in therapy

2016 ◽  
Vol 29 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Magdalena Polakowska ◽  
Jolanta Orzelska-Gorka ◽  
Sylwia Talarek
Keyword(s):  
Nitric Oxide ◽  
Central Nervous System ◽  
Nervous System ◽  
Cardiovascular Diseases ◽  
Significant Role ◽  
Current Understanding ◽  
Physiological Processes ◽  
Wide Range ◽  
The Central Nervous System ◽  
Pharmacological Profiles

AbstractNitric oxide (NO) is a relatively novel messenger that plays a significant role in a wide range of physiological processes. Currently, it is known that, both, lack and excess of NO can cause diseases, thus a lot of substances have been discovered and utilized which can change the concentration of this molecule within the organism. The aim of the present work is to provide an overview of currently used agents modulating the L-arginine:NO:cGMP pathway, as well as to summarize current understanding of their pharmacological profiles. Nowadays, most of these agents are employed particularly in the treatment of cardiovascular diseases. Further studies can hold promise for enhancing the therapeutic equipment for a variety of other impairments, such as osteoporosis, and also in treatments of the central nervous system.

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