Effects of parasitism on the octopamine content of the central nervous system of Manduca sexta: a possible mechanism underlying host behavioural change

2000 ◽  
Vol 78 (9) ◽  
pp. 1580-1587 ◽  
Author(s):  
Shelley A Adamo ◽  
Kelly L Shoemaker
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
High Performance ◽  
Behavioural Change ◽  
Parasitic Wasp ◽  
Temporal Correlation ◽  
High Performance Liquid Chroma ◽  
Host Feeding ◽  
The Central Nervous System

The parasitic wasp Cotesia congregata lays its eggs inside the larva of Manduca sexta (tobacco hornworm). Beginning about 12 h before the wasp larvae emerge from the host, host feeding and locomotion decline. The octopamine content of the central nervous system (CNS) of parasitized hosts was measured using high-performance liquid chroma tography with electrochemical detection. Concomitant with the decrease in host feeding and locomotion, the octopamine content of the host's brain (supra- and sub-esophageal ganglia), thoracic ganglia, and abdominal ganglia increased. In nonparasitized M. sexta, the octopamine content of the CNS did not change significantly during moult sleep, a stage in which the behaviour superficially resembles that of M. sexta after the wasps have emerged. Neither result is consistent with the hypothesis that the octopamine content within the CNS is lower in inactive insects. Nevertheless, the close temporal correlation between the change in host behaviour and CNS octopamine content suggests that alterations in the functioning of the octopaminergic system may play a role in depressing host feeding and (or) locomotion.

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.

FMRFamide-like immunoreactivity in the crayfish nervous system

1991 ◽  
Vol 156 (1) ◽  
pp. 519-538
Author(s):  
A. J. Mercier ◽  
I. Orchard ◽  
V. TeBrugge
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Synthetic Peptide ◽  
High Performance ◽  
Procambarus Clarkii ◽  
Reversed Phase ◽  
Neuronal Somata ◽  
Extraction And Separation ◽  
Rp Hplc ◽  
The Central Nervous System

FMRFamide-like immunoreactivity (FLI) was detected in the nervous system of the crayfish Procambarus clarkii using an antiserum that recognizes extended RFamide peptides. Immunocytochemistry revealed FLI in neuronal somata, axons and varicose processes within the central nervous system. In the periphery, plexuses of immunoreactive varicosities were present in the pericardial organs (POs), in thoracic roots and on the hindgut. The hindgut plexus arose from 3–5 axons leaving the sixth abdominal ganglion (A6) via the intestinal nerve. The presence of FLI in these locations was confirmed by radioimmunoassay. In contrast, no FLI was detected in motor axons innervating exoskeletal muscles of the abdomen. The POs contained by far the largest amount of FLI of all tissues examined. The immunoreactive material was partially characterized by extraction and separation on two consecutive reversed-phase high performance liquid chromatography (RP-HPLC) columns. The largest amount of immunoreactivity on the second column co-eluted with a synthetic peptide, SDRNFLRFamide (F2), previously identified as one of two or more FMRFamide-related peptides contained in lobster POs. The immunoreactive fractions and peptide F2 elicited similar effects on isolated crayfish hearts; all increased the rate and amplitude of spontaneous cardiac contractions. As with the immunoreactivity, the highest level of bioactivity was contained in the fraction that co-eluted with F2. The results suggest that FMRFamide-related peptides act as neurohormones in crayfish and are likely to play roles in controlling circulation and defecation.

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 Cerebrospinal fluid ceftazidime kinetics in patients with external ventriculostomies.

1996 ◽  
Vol 40 (3) ◽  
pp. 763-766 ◽  
Author(s):  
R Nau ◽  
H W Prange ◽  
M Kinzig ◽  
A Frank ◽  
A Dressel ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Cerebrospinal Fluid ◽  
Nervous System ◽  
High Performance ◽  
Elimination Half ◽  
Daily Dose ◽  
Order Of Magnitude ◽  
The Central Nervous System ◽  
Occlusive Hydrocephalus ◽  
A Minor

Ceftazidime has proven to be effective for the treatment of bacterial meningitis caused by multiresistant gram-negative bacteria. Since nosocomial central nervous system infections are often accompanied by only a minor dysfunction of the blood-cerebrospinal fluid (CSF) barrier, patients with noninflammatory occlusive hydrocephalus who had undergone external ventriculostomy were studied (n = 8). Serum and CSF were drawn repeatedly after the administration of the first dose of ceftazidime (3 g over 30 min intravenously), and concentrations were determined by high-performance liquid chromatography by using UV detection. The concentrations of ceftazidime in CSF were maximal at 1 to 13 h (median, 5.5 h) after the end of the infusion and ranged from 0.73 to 2.80 mg/liter (median, 1.56 mg/liter). The elimination half-lives were 3.13 to 18.1 h (median, 10.7 h) in CSF compared with 2.02 to 5.24 h (median, 3.74 h) in serum. The ratios of the areas under the concentration-time curves in CSF and serum (AUCCSF/AUCS) ranged from 0.027 to 0.123 (median, 0.054). After the administration of a single dose of 3 g, the maximum concentrations of ceftazidime in CSF were approximately four times higher than those after the administration of 2-g intravenous doses of cefotaxime (median, 0.44 mg/liter) and ceftriaxone (median, 0.43 mg/liter) (R. Nau, H. W. Prange, P. Muth, G. Mahr, S. Menck, H. Kolenda, and F. Sörgel, Antimicrob. Agents Chemother. 37:1518-1524, 1993). The median AUCCSF/AUCS ratio of ceftazidime was slightly below that of cefotaxime (0.12), but it was 1 order of magnitude above the median AUCCSF/AUCS of ceftriaxone (0.007) (Nau et al., Antimicrob. Agents Chemother. 37:1518-1524, 1993). The concentrations of ceftazidime observed in CSF were above the MICs for most Pseudomonas aeruginosa strains. However, they are probably not high enough to be rapidly bactericidal. For this reason, the daily dose should be increased to 12 g in cases of P. aeruginosa infections of the central nervous system when the blood-CSF barrier is minimally impaired.

scholarly journals Several forms of callitachykinins are distributed in the central nervous system and intestine of the blowfly Calliphora vomitoria.

1995 ◽  
Vol 198 (12) ◽  
pp. 2527-2536
Author(s):  
D R Nässel ◽  
M Y Kim ◽  
C T Lundquist
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
High Performance ◽  
The Body ◽  
Enzyme Linked Immunosorbent Assay ◽  
Additional Material ◽  
Immunoreactive Material ◽  
The Central Nervous System ◽  
Entire Central Nervous System ◽  
The Brain

We have examined the distribution of two tachykinin-related neuropeptides, callitachykinin I and II (CavTK-I and CavTK-II), isolated from whole-animal extracts of the blowfly Calliphora vomitoria. Extracts of dissected brains, thoracic-abdominal ganglia and midguts of adult blowflies and the entire central nervous system of larval flies were analysed by high performance liquid chromatography (HPLC) combined with enzyme-linked immunosorbent assay (ELISA) for the presence of CavTKs. To identify the two neuropeptides by HPLC, we used the retention times of synthetic CavTK-I and II as reference and detection with an antiserum raised to locustatachykinin II (shown here to recognise both CavTK-I and II). The brain contains only two immunoreactive components, and these have exactly the same retention times as CavTK-I and II. The thoracic-abdominal ganglia and midgut contain immunoreactive material eluting like CavTK-I and II as well as additional material eluting later. The larval central nervous system (CNS) contains material eluting like CavTK-I and II as well as a component that elutes earlier. We conclude that CavTK-I and II are present in all assayed tissues and that additional, hitherto uncharacterised, forms of tachykinin-immunoreactive material may be present in the body ganglia and midgut as well as in the larval CNS. An antiserum was raised to CavTK-II for immunocytochemistry. This antiserum, which was found to be specific for CavTK-II in ELISA, labelled all the neurones and midgut endocrine cells previously shown to react with the less selective locustatachykinin antisera. It is not clear, however, whether CavTK-I and II are colocalised in all LomTK-immunoreactive cells since there is no unambiguous probe for CavTK-I.

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