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PubMed1979

Glucocorticosteroid receptors in the liver of normal and decapitated rabbit foetuses.

The affinity and the number of receptor sites for the synthetic steroid triamcinolone acetonide were studied in the livers of foetal rabbits. Twenty-two-, 24- and 29-day-old control and 29-day-old foetuses decapitated on day 22 were used to determine whether a change in steroid receptors occurs in the liver when it accumulates glycogen, and whether decapitation impairs such a change. Steroid receptors were found as early as day 22, when they were as numerous (0.091 pmol/mg protein) as on days 24 (0.098 pmol/mg) and 29 (0.104 pmol/mg). The binding affinity was found to be slightly higher on day 24 than on day 22 and it remained the same on days 24 and 29. The binding affinity of the receptors was the same in decapitated foetuses as in 29-day-old controls but the number of sites was slightly lower. The labelled steroid was transferred to the nucleus of the liver cells in vivo. It seems unlikely that steroid receptors are the limiting factor preventing the accumulation of glycogen in the liver of the rabbit foetus before day 26 or after decapitation.

Animals↗

PubMed1989

Ether as an anesthetic for decapitation in the rat: gonadotropin secretion by subsequently established anterior pituitary cell cultures.

Historically, for the establishment of dispersed anterior pituitary cell cultures, rodents have been killed by decapitation without anesthesia. Because decapitation fails to induce immediate unconsciousness, the American Veterinary Medical Association Panel on Euthanasia has recently recommended that rodents should not be decapitated without previous anesthesia or sedation. Investigators are therefore confronted with the dilemma of wishing to euthanize rodents humanely yet not wishing to potentially compromise experimental data through the use of anesthetics. We present our observations on the effects of diethyl ether anesthesia administered prior to decapitation on the gonadotropin secretory characteristics exhibited in vitro by cultured rat anterior pituitary cells. Neither light nor complete (surgical level) ether anesthesia had any statistically significant effect on either luteinizing hormone or follicle-stimulating hormone responsiveness or cell content of luteinizing hormone and follicle-stimulating hormone or DNA content. The data indicate that ether anesthesia would appear to be acceptable for those studies involving subsequent in vitro luteinizing hormone and follicle-stimulating hormone secretion.

Animals↗

PubMed1975

EEG evaluation of humaneness of asphyxia and decapitation euthanasia of the laboratory rat.

The relative humaneness of asphyxia and decapitation was objectively evaluated in rats by EEG monitoring. EEG activation (low voltage, fast activity) was considered to indicate discomfort, pain, and affective responses to euthansia. Such activation was present 37.3 plus or minus 7.5 sec after asphyxia and 13.6 plus or minus 4,6 sec after decapitation. Decapitation was also characterized by an immediate large, and relatively long-lasting, ultra-slow voltage, detected by non-polarizable scalp electrodes. Isoelectric activity (death) occurred 69.4 plus or minus 9.9 sec after onset of asphyxia and 27.2 plus or minus 4.4 sec after decapitation.

Action Potentials↗

PubMed1992

Effects of surgical decapitation and chicken growth hormone (cGH) replacement therapy on chick embryo growth.

The effects of decapitation and chicken growth hormone (cGH) replacement therapy on chick embryo growth has been investigated. Removal of the prosencephalon at 33-38 hrs (1.38 to 1.58 Days) of incubation decreased body (torso) and liver weights as well as skeletal growth as indicated by tibial length. A single pituitary gland transplanted onto the chorioallantoic membrane (CAM) partially restored torso growth and completely reversed the increase in body water content which characterizes decapitated embryos. Replacement therapy with cGH did not influence body weight but did, on Day 16.5 of incubation, increase tibial length and liver DNA content and concentration. These latter findings suggest that there may be limited hypothalamoadenohypophyseal (GH) axis function in the chick embryo. The effects of decapitation on torso growth are also discussed in conjunction with decapitation effects on albumen swallowing (absorption) and yolk absorption.

Albumins↗

PubMed2003

[Effects of grazing, cutting and decapitating on grass populations on the artificial grassland in subtropical zone of China].

Studies on the effects of grazing, cutting and decapitating on grass populations on the artificial grassland in the subtropical zone of China showed that moderate grazing and cutting could increase the adaptability of Dactylis glomerata and Lolium prenn due to decapitating. Decapitating could rescind the apical dominance and reproduction growth of grass, and hence, the ecological effects of grazing and cutting on grass could be realized by decapitating, and the population density, caloric value and energy accumulation of Dactylis glomerata and Lolium prenn increased obviously. Apical dominance of grasses could lower the population density, energy accumulation and intra-population competitive ability.

Animal Feed↗

PubMed1990

[Morphological changes and sperm decapitation as a cause of fertility disorders in breeding stock].

Decapitation of spermatozoa was recorded in a young boar as a consequence of epididymitis and in a young dog (mastiff) and a young bull (Brown Swiss breed) as a congenital cause of the subfertility and sterility of the affected animal. Decapitation of spermatozoa as a consequence of an inflammation led to the sterility of the breeding male and affected 52 to 68% of the spermatozoa. The motility of the spermatozoa was reduced considerably (10 to 20%) and the flagella were not observed to move without the heads. In cases of congenital decapitation of spermatozoa, sperm motility in the dog and bull was reduced, but the flagella were observed to move without the heads. Decapitation affected 15 to 42% of the spermatozoa and most frequently it was accompanied by a narrowing of head base and by the presence of a protoplasmic drop, located proximally. Further developmental changes, affecting the flagella of the sperms, were observed in the dog. The mentioned morphological changes led to infertility in the dog and to a substantial reduction of fertility in the bull. After natural mating of the bull with a superovulated cow, the ten eggs obtained included four blastocysts, two were degenerated, and four were unfertilized.

Animals↗

PubMed1989

[Effect of anesthesia and/or decapitation on the mechanical behavior of papillary muscles isolated from the left ventricle of the rat].

The mechanical performance of isometrically contracting papillary muscle was studied in rats sacrificed by decapitation or anesthetized with sodium pentobarbital or chloralose before decapitation. The purpose was to evaluate which maneuver would be the more adequate to ve used, when performance of papillary muscle mechanics must be evaluated later. The data suggest that either anesthetic agents used in this experiment and/or decapitation have the same effects on isolated muscle performance in the three groups. The results may be a consequence of the time elapsed between animal decapitation and the recording of cardiac parameters: this fact would attenuate the many factors that could promote mechanical performance dysfunction or isolated papillary muscles.

Analysis of Variance↗

PubMed1981

The increase of cerebellar cAMP level after decapitation: the effect of propranolol.

The increase of cAMP level of the rat cerebellum induced by decapitation was studied. Administration of 5 mg/100 g propranolol 1 hour before decapitation completely prevented this increase. Neither the depletion of catecholamine pools, inhibition of their synthesis, nor barbiturate treatment influenced the increase of cAMP level evoked by decapitation. It has been concluded that noradrenergic neurotransmission is involved in the cerebellar cAMP level increase after decapitation.

Animals↗

PubMed1989

Morphogenesis of the decapitated and decaudated sperm defect in two brothers.

The "decapitated sperm" defect, found in both of two sterile brothers, may be assumed to have a genetic origin. The present material suggests that the term "decapitated spermatozoa" is not exact, because detached heads and tails were found in the brothers' ejaculate that could be regarded as "decapitated tails" and "decaudated heads." The present report describes frequent, more or less advanced stages of detachment. Both heads and tails showed a normal structure in which only the postnuclear region was deficient, lacking basal plate and implantation fossa. A break at a different level of the midpiece, and therefore three kinds of separation, were observed. The defect, according to the present research, must originate in the testicular region, whereas the detachment occurs in the epididymis.

Adult↗

PubMed1983

Nerve endings in the pulmonary trunk, ductus arteriosus and aorta of intact and decapitated pig fetuses.

Nerve fibres reactive to acetyl-thiocholine, and tissues showing catecholamine fluorescence were examined in the pulmonary trunk, ductus arteriosus and aorta of 28 pig fetuses between 31 and 113 days of gestation (term = 114 +/- 1 days). Eight additional fetuses, which had been decapitated in utero at 40-43 days, were also studied at ages between 51 and 114 days of gestation. Spherical micro-networks of nervous tissue reactive to acetyl-thiocholine are present in the adventitia on the cranial aspect of the pulmonary trunk and ductus arteriosus, between the aorta and pulmonary trunk, and on the caudal aspects of the pulmonary trunk and the pulmonary arteries. These fibres invest spherical clusters of catecholamine containing cells which are well supplied with blood vessels. Nerve fibres which fluoresce are also found in association with these cells. Decapitation in utero does not appear to affect the distribution of morphology of these structures. The observations show that structures are present in the major arteries of the fetal pig which may act as sensory receptors, and that these structures are unaffected by chronic vagotomy of the fetus produced by decapitation early in gestation.

Animals↗

PubMed1983

Development of nervous tissue in the heart of the fetal and neonatal pig and the effect of decapitation in utero.

The development and distribution of the nerves in the heart of the pig was studied macroscopically and by light microscopy. Hearts were collected from 86 fetuses between 31 and 114 days of gestation (term = 114 days), from 12 neonatal pigs aged 9 and 20 days and from 6 adult sows of the Dutch Landrace breed. The effect of vagotomy produced by decapitation in utero at 40-43 days was studied in an additional 24 hearts from fetuses aged between 51 and 114 days of gestation. The amount of acetyl-thiocholine reactive fibres increases in the atria, A-V node and ventricles throughout gestation. At every age the amount of nervous tissue is highest in the A-V node and lowest in the ventricles. Hearts from decapitated fetuses have smaller amounts of nerve tissue than those from intact fetuses at every age studied. Ganglia are present in both intact and decapitated fetuses. Fluorescent cells containing catecholamines are observed in hearts from fetuses as young as 35 days gestation. Although fluorescent nerve fibres are rarely seen in hearts at 70 days gestation, more fibres are present near birth and thereafter there appears to be a considerable increase in the number of fibres and in the intensity with which they fluoresce. These results show that there is substantial nerve growth into the heart of the pig during gestation and that catecholamine containing nerve fibres develop later than those reactive to acetyl-thiocholine.

Animals↗

PubMed2001

Auxin promotes gibberellin biosynthesis in decapitated tobacco plants.

Excision of the apical bud (decapitation) of tobacco (Nicotiana tabacum L.) plants reduced the endogenous levels of indole-3-acetic acid (IAA), gibberellin A20 (GA20), and GA1 (the bioactive GA), in internode tissue below the excision site. Application of IAA to the stump of decapitated plants dramatically increased GA20 content, to a level 3-fold greater than in intact plants. Gibberellin A1 content was also increased by IAA. Decapitation reduced the conversion of [14C]GA19 to [14C]GA20 and of [14C]GA20 to [14C]GA1, and appeared to promote the deactivation pathway [14C]GA20 to [14C]GA29 to [14C]GA29-catabolite. Application of auxin counteracted these effects, but did not restore the conversion of [14C]GA20 to [14C]GA1 to the level found in intact plants. The results indicate that auxin is necessary for normal GA biosynthesis in stems of tobacco.

Carbon Radioisotopes↗

PubMed1983

alpha-Tocopherol and ubiquinones in rat brain subjected to decapitation ischemia.

Levels of alpha-tocopherol (alpha-Toc), reduced ubiquinones (QH2) and oxidized ubiquinones (Q) were assayed in rat forebrain subjected to decapitation ischemia. Post-decapitation levels of alpha-Toc decreased by 16% at 3 min and 20% at 15 min. Increases in Q9H2 (83%) and in Q10H2 (107%) were observed immediately following decapitation; thereafter their levels began to decrease and approached to the pre-ischemic values at 15 min. In contrast, Q9 and Q10 tended to increase continuously during ischemia. The data indicate that complete ischemia results in distinct changes in the cerebral content of lipid-soluble antioxidants. The decrease of alpha-Toc may make the brain prone to peroxidative attack when cerebral tissue is subsequently reoxygenated.

Animals↗

PubMed1984

Pre-decapitation state of arousal of rats predetermines the effect of des-Tyr1-gamma-endorphin on dopamine release from nucleus accumbens slices in vitro.

The non-opiate beta-endorphin fragment des-Tyr1-gamma-endorphin (DT gamma E) had a decreasing effect on K+-induced release of tritiated dopamine from nucleus accumbens slices in vitro, when tissue was used of rats which prior to decapitation were in a state of low arousal. When nucleus accumbens tissue was used of rats which were mildly stressed by exposure to a novel environment prior to decapitation, this effect was absent, while an enhancing effect of DT gamma E became evident on basal dopamine efflux. This latter effect resembled that of haloperidol, which dose-dependently enhanced basal dopamine efflux in vitro. Exposure of rats to ether vapor shortly before decapitation abolished both these in vitro effects of DT gamma E. The results are interpreted as indicating that the quality of the modulating effects of DT gamma E on dopamine release from dopaminergic neurons projecting to the nucleus accumbens is depending on the state of activity of these neurons, which, in its turn, is a reflection of the state of arousal of the rats.

Animals↗

PubMed1990

Neuropeptides in brain: effects of microwave irradiation and decapitation.

Substance P (SP)-, neurokinin A (NKA)-, neurotensin (NT)-, neuropeptide Y (NPY)- and vasoactive intestinal polypeptide (VIP)-like immunoreactivity (Ll) were measured and characterized by specific radioimmunoassays (RIA) and reverse phase high performance liquid chromatography (HPLC) in extracts of rat brain. Concentrations of SP-Ll, NKA-Ll and NT-Ll in brains of decapitated animals were 59, 49 and 64 percent lower compared to those found in animals sacrificed by focused microwave irradiation (MW). In contrast, no difference in brain NPY-Ll and VIP-Ll levels was found between animals killed by MW and decapitation. HPLC chromatograms of SP-, NKA-, NT- and NPY-Ll showed the same immunoreactive components in extracts of brains from both groups of animals. Thus, no additional immunoreactive components were formed by MW compared to those found after decapitation. The present findings may reflect an MW-induced inhibition of peptidase activity or, perhaps, a more efficient extraction of certain neuropeptides following MW treatment. The results imply that the traditional methods of sacrifice may result in the measurement of spuriously low tissue concentrations of some peptides, e.g. tachykinins, in brain.

Animals↗

PubMed1982

Variation of rat serum biochemical values following decapitation or anesthesia with ether, halothane or Innovar-VetR: rapid Innovar-VetR-induced hyperuricemia and hyperglycemia.

True reference values (TRV) should ultimately be determined in blood from inactive, unstimulated rats but in practice, acceptable reference values (ARV) may be established using blood from decapitated or anesthetized animals if one is cognizant of variations associated with blood sampling procedures. Data reported here illustrate some variations in serum biochemical values following decapitation or anesthesia. Decapitation does not provide serum in which ARV for sodium, potassium or lactate dehydrogenase can be found but ARV can be determined for glucose, insulin and several other parameters. It is suggested that both TRV and ARV for serum electrolytes be determined using serum from cannulated rats. All three anesthetics raised glucose levels and ether and halothane increased alkaline phosphatase activity. Both halothane and Innovar-VetR decreased insulin:glucose ratios suggesting inhibition of insulin release from the pancreas. Innovar-VetR also produced hypoxia due to severe respiratory depression and bradycardia as well as hyperuricemia, hyperglycemia and hyperphosphatemia. Techniques most likely to provide ARV should be of the shortest possible duration, afford least respiratory and cardiovascular suppression and minimize stimulation of the sympathetic nervous system.

Anesthetics↗

PubMed1983

The effects of gestational age and chronic fetal decapitation on arterial blood pressure in the pig fetus.

Blood pressure was measured in anaesthetized pig fetuses decapitated at 40-43 days of gestation and in intact fetuses between 35 and 112 days of gestation (term is 114 days). In the intact fetuses arterial blood pressure increased significantly from 0.8 +/- 0.1 kPa (mean +/- SEM) at 35 days to 5.8 +/- 0.2 kPa at 112 days (P less than 0.05). The arterial blood pressure of decapitated fetuses was similar to that of intact fetuses at 70 days of gestation (2.7 +/- 0.4 kPa vs. 2.5 +/- 0.1 kPa, respectively) but did not change with increasing gestational age thereafter. Hence in late gestation (greater than 90-100 days) the arterial blood pressure of the decapitated fetuses was significantly less than that of intact fetuses (P less than 0.05). These observations demonstrate that the control of blood pressure in the pig varies with gestational age and suggest that the developmental changes occurring after about 100 days gestation require tissues within the head.

Animals↗

PubMed1989

Decapitation increases plasma sodium and potassium in the rat.

Sodium, potassium, and osmolality were measured in plasma obtained from conscious and decapitated rats. The sodium and potassium content of plasma derived from blood taken from decapitated rats via arterial cannulae or free-flowing trunk blood was significantly greater than that in conscious animals or animals killed by an overdose of pentobarbital. Plasma osmolality was not different. Hemoglobin was present in the plasma of decapitated rats, suggesting hemolysis. Hemolysis and subsequent release of intracellular potassium may be the cause of the elevated plasma potassium. The cause of the elevated sodium is unclear. This study points out the importance of considering the method of obtaining blood in determinations of plasma levels of biologic substances.

Animals↗