Parasite-induced learned taste aversion involving Nippostrongylus in rats

Parasitology ◽  
1983 ◽  
Vol 86 (3) ◽  
pp. 455-460 ◽  
Author(s):  
Anne Keymer ◽  
D. W. T. Crompton ◽  
B. J. Sahakian
Keyword(s):  
Food Intake ◽  
Taste Aversion ◽  
Parasitic Infection ◽  
Nippostrongylus Brasiliensis ◽  
Experimental Demonstration ◽  
Simultaneous Choice ◽  
Third Stage ◽  
Inductive Agent ◽  
Subcutaneous Inoculation

SUMMARYAfter demonstrating that rats were capable of discriminating between the same diet treated with either flavour 1 or flavour 2 and that the 2 flavours of diet were equipreferred, an experiment was carried out to see whether learned taste aversion might play a role in the reduction of food intake that is commonly observed during the course of a parasitic infection. The results showed that rats, given a subcutaneous inoculation of approximately 6000 third-stage larvae of Nippostrongylus brasiliensis (Nematoda) while feeding on a diet containing flavour 2, strongly preferred to eat diet containing flavour 1 when given simultaneous choice conditions. Uninfected rats showed no preference and ate equal amounts of both flavoured diets. This effect is interpreted as the first experimental demonstration of learned taste aversion using a eukaryotic parasite as the inductive agent.

Estimation of the numbers and infectivity of Nippostrongylus larvae

1983 ◽  
Vol 57 (3) ◽  
pp. 225-230 ◽  
Author(s):  
Anne Keymer ◽  
Jean Martin ◽  
S. M. Wainwright
Keyword(s):  
Small Intestine ◽  
Inoculum Size ◽  
Experimental Investigations ◽  
Nippostrongylus Brasiliensis ◽  
Subcutaneous Infection ◽  
Laboratory Conditions ◽  
Level Of Confidence ◽  
Third Stage ◽  
Age Dependent ◽  
Subcutaneous Inoculation

ABSTRACTExperimental investigations of the subcutaneous infection of third-stage larvae of Nippostrongylus brasiliensis reveal discrepancies between the actual and intended inoculum, and also variability between replicate inocula. Emphasis is thus placed on the importance of obtaining accurate estimates of the level of confidence associated with inoculum size. Under specified laboratory conditions, the retention of infectivity of N. brasiliensis larvae was found to be age-dependent, with a maximum of between 120 and 156 days. The motility of the larvae was not found to be indicative of their ability to complete migration and to become established in the small intestine of the host following subcutaneous inoculation.

scholarly journals Gfral-expressing Neurons Suppress Food Intake via Aversive Pathways

2020 ◽  
Author(s):  
Paul V. Sabatini ◽  
Henriette Frikke-Schmidt ◽  
Joe Arthurs ◽  
Desiree Gordian ◽  
Anita Patel ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Food Intake ◽  
Taste Aversion ◽  
Conditioned Taste Aversion ◽  
Mechanisms Of Action ◽  
Parabrachial Nucleus ◽  
Gastric Physiology ◽  
Anorexigenic Peptide ◽  
Artificial Activation ◽  
Meal Ingestion

AbstractTo determine the function and mechanisms of action for hindbrain neurons that express GFRAL, the receptor for the anorexigenic peptide, GDF-15, we generated Gfralcre and conditional GfralCreERT mice. While signals of infection or pathophysiologic states (rather than meal ingestion) stimulate GFRAL neurons, the artificial activation of GfralCre- expressing neurons inhibited feeding, decreased gastric emptying, and promoted a conditioned taste aversion (CTA). Additionally, activation of the smaller population of GFRAL neurons captured by the GfralCreERT allele decreased gastric emptying and produced a CTA without suppressing food intake, suggesting that GFRAL neurons primarily modulate gastric physiology and stimulate aversive responses. GFRAL neurons most strongly innervated the parabrachial nucleus (PBN), where they targeted CGRP-expressing (CGRPPBN) neurons. Silencing CGRPPBN neurons abrogated the aversive and anorexic effects of GDF-15. These findings suggest that GFRAL neurons link non-meal-associated, pathophysiologic signals to the aversive suppression of nutrient uptake and absorption.

Immunization of Guineapigs against Ascaris suum

1960 ◽  
Vol 34 (3-4) ◽  
pp. 347-348 ◽  
Author(s):  
L. F. Taffs
Keyword(s):  
Control Group ◽  
Group Iii ◽  
Successful Attempt ◽  
Group I ◽  
Third Stage ◽  
Previous Infection ◽  
Group Ii ◽  
Intravenous Inoculation ◽  
Subcutaneous Inoculation ◽  
Control Group Group

It has been shown that guineapigs can be effectively protected against re-infection by the subcutaneous inoculation of embryonated Ascaris eggs (Soulsby, 1957). The purpose of this communication is to report a successful attempt to immunize guineapigs against a lethal oral challenge dose of eggs by the intravenous inoculation of third stage larvae of A. suum.Three groups, each containing nine guineapigs, were infected with Ascaris as follows: Group I was given 10,000 eggs by mouth. Group II Was inoculated intravenously with 2,000 third stage Ascaris larvae which had been obtained from the lungs of other guineapigs on the sixth day of infection. Both groups were challenged at the same time with 250,000 eggs by mouth, along with a control group (Group III) which had no previous infection. The guineapigs in Group I were re-infected after 18 days and those in Group II after 12 days.

Physiological responses of rats to primary infection with Nippostrongylus brasiliensis

1986 ◽  
Vol 60 (4) ◽  
pp. 307-312 ◽  
Author(s):  
K. S. Ovington
Keyword(s):  
Food Intake ◽  
Primary Infection ◽  
Physiological Responses ◽  
Host Responses ◽  
Nippostrongylus Brasiliensis ◽  
Intestinal Nematode ◽  
Microbial Infections ◽  
Rate Of Oxygen Consumption ◽  
Muscle Catabolism ◽  
Ad Libitum

ABSTRACTThe physiological responses of well-nourished rats to primary infection with the intestinal nematode Nippostrongylus brasiliensis were examined. Infected rats fed ad libitum were compared with uninfected control rats fed ad lib. and also with uninfected rats which were pair-fed to the infected rats. Following infection with N. brasiliensis rat food intake was reduced from day 2 post infection (pi) and there were two periods of minimal food intake (day 2 to 3 and 8 to 9 pi). The water intake of infected rats was only reduced on days 2, 3 and 9 pi and not to the same extent as food intake. Muscle catabolism in infected rats was more severe than could be explained on the basis of their food intake reduction. The rectal temperature and rate of oxygen consumption per g body-weight of rats was not significantly altered by the infection. Host responses to N. brasiliensis are compared with those seen in microbial infections and some of them are found to be considerably different.

Fluctuations in rat liver alanine-amino-transferase activity during experimental nippostrongylosis

Parasitology ◽  
1989 ◽  
Vol 98 (2) ◽  
pp. 301-306
Author(s):  
Lucy J. Robertson
Keyword(s):  
Immune Response ◽  
Primary Infection ◽  
Parasitic Infection ◽  
Transferase Activity ◽  
Nippostrongylus Brasiliensis ◽  
Alanine Amino Transferase ◽  
A Value ◽  
Gluconeogenic Enzyme ◽  
Alt Activity

SUMMARYThe activity of the gluconeogenic enzyme, alanine-amino-transferase (ALT), in a preparation from the liver of rats was studied by means of an in vitro assay throughout the course of a primary infection of Nippostrongylus brasiliensis, established by a subcutaneous injection of approximately 4000 3rd-stage larvae. The activity was measured on days 1–14 p.i. in both uninfected and infected rats and a marked pattern in the enzyme's activity was observed. In infected rats, the activity increased from 1·46±0·19 U/g liver on day 1 p.i. to a peak on day 4 p.i. of 10·75±1·62 U/g liver, then decreased to a trough of 0·44±0·18 U/g liver on day 10 p.i. before returning to original levels by day 14 p.i., by which time the infection had been largely eliminated. In uninfected rats the activity of the liver enzyme remained constant throughout this period with a value of 2·54±0·12 U/g liver. The activity of the enzyme in vitro was found to be related to the size of the inoculum on days 4 and 10 p.i. It was proposed that these observations could be due to either (1) a direct effect of the parasite, or (2) a consequence of the host immune response to the infection. In order to investigate the second proposition more fully, liver ALT activity was investigated by in vitro assay on selected days p.i. in rats experiencing a secondary N. brasiliensis infection. In these rats the liver ALT activity was observed to reach a peak on day 2 p.i., with an activity of 3·87 ± 0-28 U/g liver, and a trough on day 4 p.i. with an activity of 0·11 ±0·03 U/g liver, returning to similar levels to those measured in uninfected rats by day 7 p.i. When serum prepared from rats having secondary N. brasiliensis infections collected on day 4 p.i. was added to the assay, a reduction in the activity of liver ALT activity from both the infected and uninfected rats was measured by in vitro assay. The results are discussed in relation to protein metabolism and gluconeogenesis in rats infected with N. brasiliensis, and also in relation to the host’s immune response to the parasitic infection.

Two novel paradigms for the simultaneous assessment of conditioned taste aversion and food intake effects of anorexic agents

2003 ◽  
Vol 79 (4-5) ◽  
pp. 761-766 ◽  
Author(s):  
S BENOIT ◽  
E AIR ◽  
K WILMER ◽  
P MESSERSCHMIDT ◽  
K HODGE ◽  
...  
Keyword(s):  
Food Intake ◽  
Taste Aversion ◽  
Conditioned Taste Aversion ◽  
Simultaneous Assessment

Changes in the food intake and body weight of protein-malnourished rats infected with Nippostrongylus brasiliensis (Nematoda)

Parasitology ◽  
1981 ◽  
Vol 82 (1) ◽  
pp. 23-38 ◽  
Author(s):  
D. W. T. Crompton ◽  
D. E. Walters ◽  
Susan Arnold
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Infected Group ◽  
Nippostrongylus Brasiliensis ◽  
Initial Weight ◽  
Daily Food Intake ◽  
Young Rats ◽  
Daily Food ◽  
Long Duration ◽  
Ad Libitum

SUMMARYThe daily food intake and related changes in body weight were measured in young rats which were fed on synthetic diets containing 1% (3 experiments), 2% (4 experiments) and 20% (1 experiment) casein respectively. Some rats were infected with Nippostrongylus brasiliensis and allowed to feed ad libitum, some remained uninfected and were allowed to feed ad libitum while others, which were matched by initial weight with rats from the infected group, remained uninfected and were given only the same amount of food as that consumed during the previous 24 h by their infected partners. No significant differences were detected between the rats before the start of the infection. Thereafter, the food intake of the infected undernourished rats was usually found to be significantly lower and the loss of body weight significantly greater than those of the uninfected rats. In infection periods of relatively long duration, the pair-fed uninfected rats did not lose as much weight as their infected partners even though their food intake (1% and 2% casein) was the same. Although the food intake, and consequently the weight, of infected rats fed on the diet containing 20% casein were significantly less than in their uninfected partners, no significant differences were observed between the weights of the infected and pair-fed rats fed on this diet.

The degradation rates of cytoplasmic tRNA, rRNA and mRNA in rats are elevated after infection with Nippostrongylus brasiliensis

Parasitology ◽  
1998 ◽  
Vol 116 (2) ◽  
pp. 197-201 ◽  
Author(s):  
H. TOPP ◽  
R. DUDEN ◽  
U. STEPHAN ◽  
G. SCHÖCH
Keyword(s):  
Reactive Oxygen Species ◽  
Post Infection ◽  
Renal Excretion ◽  
Parasitic Infection ◽  
Reactive Oxygen ◽  
Nippostrongylus Brasiliensis ◽  
Oxygen Species ◽  
Degradation Rates ◽  
Excretion Rates

The effects of a parasitic infection with the nematode Nippostrongylus brasiliensis on the degradation rates of cytoplasmic tRNA, rRNA and mRNA in rats have been investigated by measuring the renal excretion rates of the modified RNA catabolites N6-threoninocarbonyladenosine, pseudouridine and 7-methylguanine. Between days 9 and 13 post-infection when the expulsion of N. brasiliensis is usually the most pronounced, the degradation rates of the different RNA classes were significantly higher than in the control rats (P<0·05) by, on average, +24% (tRNA), +34% (rRNA) and +26% (mRNA). We suspect that the elevated degradation rates of RNA are related to an increased production of reactive oxygen species by the host during the expulsion of N. brasiliensis.

A technique for skin application of exact doses ofNippostrongylus brasiliensisto rats

1990 ◽  
Vol 64 (1) ◽  
pp. 15-22 ◽  
Author(s):  
N. R. Tindall ◽  
P. A. G. Wilson
Keyword(s):  
Experimental Design ◽  
Quantitative Agreement ◽  
Nippostrongylus Brasiliensis ◽  
The Third ◽  
Third Stage ◽  
The Mean ◽  
Conventional Methods ◽  
Polythene Film ◽  
New System

ABSTRACTConventional methods for percutaneous infection of rats using third-stage juveniles ofNippostrongylus brasiliensiswhich have been artificially stimulated to exsheath lead to highly variable, and relatively poor, establishment in the intestine. A new system has been developed in which larvae applied to the skin still remain partially sheathed, as they would be in nature. Cultures of the freeliving stages of the parasite contain an annulus of clear, colourless polythene film to which some of the third-stage juveniles attach. Rats are infected with an individually counted, exact dose applied to the skin on polythene. Using this technique (‘EDT20Nb’), consistently high values for the mean proportion of the dose that becomes establishedhave been obtained, along with a variance well below the normally accepted level (from a total of 73 rats in 12 separate assays). In particular, the added component of variance between assays in this study was insignificant, so that the probability of quantitative agreement in replicate experiments based on the method is high. It is recommended for an experimental design in which small numbers of parasites can be used.

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