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PubMed1983

Ultrastructure of aortic and pulmonary baroreceptors in the domestic fowl.

Baroreceptor regions are definitely present in the arterial wall of the aorta and pulmonary arteries of the domestic fowl. In such regions, the arterial wall is modified by the interruption and absence of the elastic laminae and smooth muscle cells. The baroreceptor endings are similar ultrastructurally to the baroreceptors of the mammalian aorta and carotid sinus; therefore they are slowly adapting. Some of the amine- or peptide-containing endings, which are present in the modified regions, share the same Schwann cell with the baroreceptor endings; they probably modulate the stimulus threshold of the baroreceptor endings. Likewise, some of the cholinergic endings share the same Schwann cell with the baroreceptor endings, and may form the efferent branch of a reflex arc and thereby modify the tension of the arterial musculature which is then registered by the baroreceptor endings. There is a possibility that aminergic anc cholinergic endings interact with each other since they sometimes share the same Schwann cell. The encapsulated endings which are reported in this investigation are similar to those of the avian carotid arteries, and they, too, should be slowly adapting to pressure changes in the arterial wall.

Animals↗
PubMed1984

Density of arteriovenous anastomoses in some skin areas of the domestic fowl (Gallus domesticus).

The vascularity and the density of arteriovenous anastomoses (AVAs) were studied in the skin of the domestic fowl by using vascular injections and histological sections. The density of AVAs and associated blood vessels were low in the wattles and in the thoracic skin (five to 23 AVAs per cm2 and five to 14 AVAs per cm2, respectively), whereas the eyelids were highly vascular and contained many AVAs (170-172 AVAs per cm2). It is suggested that the blood vessels in the eyelids are important in the temperature regulation of the eye and that AVAs in the thoracic skin may contribute to the control of blood flow through the brood patch.

Animals↗
PubMed1984

Localization of corticotropin-releasing factor-containing neurons in the brain of the domestic fowl. An immunohistochemical study.

The corticotropin-releasing factor (CRF)-containing neurons were investigated in the brain of the domestic fowl by means of the peroxidase-antiperoxidase technique at the light-microscopic level. The detection of CRF-immunoreactivity was facilitated by silver intensification. CRF-containing perikarya were found in the paraventricular, preoptic and mammillary nuclei of the hypothalamus and in some extrahypothalamic areas (nuclei dorsomedialis and dorsolateralis thalami, nucleus accumbens septi, lobus parolfactorius, periaqueductal gray of the mesencephalon, nucleus oculomotorius ventralis). Immunoreactive nerve fibers and terminals were demonstrated in the external zone of the median eminence and the organum vasculosum of the lamina terminalis. These results indicate that an immunologically demonstrable CRF-neurosecretory system also exists in the avian central nervous system.

Animals↗
PubMed1989

The relationship between eggshell porosity and air space gas tensions measured before and during the parafoetal period and their effects on the hatching process in the domestic fowl.

The partial pressure of gases in the air space were measured before and during the parafoetal period for domestic fowl eggs of the same initial weight but varying in eggshell conductance. Embryos developed and hatched normally from eggs with a wide range of shell conductance and resultant air space gas partial pressures. Air space PO2 levels measured just before pipping ranged from 55 to 65 mm Hg in low and high conductance eggs, respectively, whilst PCO2 levels ranged from 75 to 55 mm Hg. With increasing shell conductance embryos membrane-penetrated and pipped the shell later, but hatch time was unaffected. Membrane penetration and external pipping appeared to occur in response to the partial pressures of gas in the air space but not in response to one particular level of air space PO2 or PCO2. During the parafoetal stage air space PO2 decreased at about 3.8 mm Hg/h and air space PCO2 increased at about 1.8 mm Hg/h and these rates of change were unaffected by eggshell conductance.

Animals↗
PubMed1992

Time-dependent codeine hypoalgesia and hyperalgesia in domestic fowl.

Recent research demonstrated that codeine produced hypoalgesia and morphine produced hyperalgesia against a noxious thermal stimulus in young domestic fowl. The bidirectional effects of these opiate agonists on nociception are inconsistent with the notion that codeine's algesic effects result through in vivo demethylation of codeine to yield morphine. In Experiment 1, the temporal pattern (15,30,60 and 120 min) of codeine (30 mg/kg) effects on thermal nociception and respiration were examined in 15-day-old cockerels. Codeine produced a time-dependent biphasic response: hypoalgesia at 15 min and hyperalgesia at 60 and 120 min. Respiration was depressed by codeine at all test intervals. To assess for opioid specificity, Experiment 2 examined the action of naloxone (5 mg/kg) on the temporal pattern (15 and 60 min) of codeine effects (30 mg/kg) on thermal nociception and respiration. Bidirectional codeine algesic effects were observed at the 15- and 60-min test intervals. Naloxone increased the codeine jump latency scores at the 15-min interval and decreased codeine jump latency scores at the 60-min interval. These results suggest that codeine engages opposed nonopioid-mediated hypoalgesic and opioid-mediated hyperalgesic nociceptive systems in this animal model. Codeine depressed respiration at both the 15- and 60-min test intervals and this respiratory depression was reversed by naloxone. These findings support the notion that codeine respiratory effects are mediated by opioid system activity.

Animals↗
PubMed1986

Tissue glycogen and lactate handling by the developing domestic fowl.

The levels of glycogen and lactate in liver, intestine, yolk sac membrane and leg and breast muscle of domestic fowl from day 10 of "in ovo" development to day 5 after hatching compared with adults have been measured and compared with the circulating concentrations in blood of glucose and lactate. Glycogen stores in most tissues increased before hatching to attain a minimum around the eclosion and then increased to adult values in muscle and liver. Lactate maintained its plasma concentrations with higher effectiveness than plasma glucose, which increased steadily up to adult levels from hatching. The study of tissue vs plasma lactate concentration ratios suggests a general activation of lactate metabolism from hatching, coinciding with the ingestion of carbohydrate-based food. Both muscles studied, as well as intestine, seem to be net lactate producers; blood cells can speculatively be considered as lactate users and liver maintains its concentration of lactate very close to that plasma, suggesting a fast utilization of this material as well as liver being the main site for control of circulating lactate.

Aging↗
PubMed1986

Tissue glycogen and lactate handling by the developing domestic fowl.

The levels of glycogen and lactate in liver, intestine, yolk sac membrane and leg and breast muscle of domestic fowl from day 10 of "in ovo" development to day 5 after hatching compared with adults have been measured and compared with the circulating concentrations in blood of glucose and lactate. Glycogen stores in most tissues increased before hatching to attain a minimum around the eclosion and then increased to adult values in muscle and liver. Lactate maintained its plasma concentrations with higher effectiveness than plasma glucose, which increased steadily up to adult levels from hatching. The study of tissue vs plasma lactate concentration ratios suggests a general activation of lactate metabolism from hatching, coinciding with the ingestion of carbohydrate-based food. Both muscles studied, as well as intestine, seem to be net lactate producers; blood cells can speculatively be considered as lactate users and liver maintains its concentration of lactate very close to that of plasma, suggesting a fast utilization of this material as well as liver being the main site for control of circulating lactate.

Aging↗
PubMed1984

5-Hydroxytryptamine in the spinal cord of the domestic fowl.

5-Hydroxytryptamine (5HT) immunoreactive fibers and varicosities are present in the gray and white matters of the adult domestic fowl spinal cord. These immunoreactive structures are densest in laminae I and II, the area around the central canal, and in the ventral horn. 5HT fibers and varicosities surround certain laminae I and II cells and large ventral horn cells. The apparent intimate relationship between dorsal horn cells and numerous 5HT structures may render them good models to study the possible role of 5HT in the modulation of nociception in the dorsal horn.

Animals↗
PubMed1975

The development of a biotin deficiency in domestic fowl given wheat-based diets.

1. Studies were done of the possible development of a biotin deficiency in domestic fowl of various ages as a result of feeding with diets composed mainly of wheat, and meat-and-bone meal. The degree of deficiency was estimated from physical symptoms, liver and kidney composition and hepatic enzyme activities. 2. Only a mild biotin deficiency developed in 3-week-old chickens and no adverse metabolic effect were found for chickens reared to 7 or 15 weeks of age or maintained for 9 months in lay on these diets, which were suspected of producing fatty liver and kidney disease in young chickens. At 3 weeks of age the deficiency was more severe the heavier the strain of chicken and the greater the rate of body-weight gain. 3. The present results question the supposition that biotin deficiency is the sole factor responsible for the development of fatty liver and kidney syndrome in young chickens.

Age Factors↗
PubMed1966

The synthesis of o-aminophenyl glucuronide in several tissues of the domestic fowl, Gallus gallus, during development.

1. Synthesis of o-aminophenyl glucuronide has been studied in tissues of the domestic fowl, Gallus gallus, during development. 2. The only route of synthesis detected is glucuronyl transfer from UDP-glucuronic acid, and evidence suggests this to be the major pathway. 3. The pathway exists in liver, to a lesser extent in kidney and alimentary tract, and possibly also in skin. It is absent from spleen and adrenal gland. 4. o-Aminophenyl glucuronide formation, UDP-glucuronyltransferase, UDP-glucuronic acid and UDP-glucose dehydrogenase exist in the embryo liver from at least 12 days of incubation. Transferase activity falls just before hatching and rises suddenly on emergence. Overall synthesis of o-aminophenyl glucuronide observed in liver slices confirms this pattern, which also occurs in kidney. UDP-glucuronyltransferase appears in intestinal mucosa only after hatching, and is absent from embryonic spleen. The allantoic membrane forms no o-aminophenyl glucuronide. 5. These findings are related to the isolated existence of an avian embryo.

Adrenal Glands↗
PubMed1992

The embryo pancreas is a source of increased yolk amylase in the fertilized eggs of domestic fowls.

The amylases were studied in the yolk of fertilized eggs and in the pancreases of the embryos of domestic fowls. The amylase activity in the yolk increased markedly from 13 days of incubation until hatching, but the activity decreased when the embryos were taken out of the eggs. The isoamylases in the yolk and in the pancreas of the embryo were identical electrophoretically. The amylase occurs mainly in the pancreas of the embryo. We think that the increase in amylase activity in the yolk of fertilized eggs during incubation depends upon the accumulation of pancreatic amylase synthesized by the developing embryo in the egg.

Amylases↗
PubMed1984

The columbian restriction gene, Co, and early growth rate in the domestic fowl.

Studies were conducted on the effects of the columbian restriction gene, Co, on early growth rate in the domestic fowl. There were no statistically significant effects of the Co gene on body weights at 4, 6, and 8 weeks of age. The importance of these findings is discussed in relationship to the desired presence of the Co gene to enhance sex identification in sex-linked crosses utilizing the silver (S) and gold (s+) alleles.

Animals↗
PubMed1987

Nuclear events from fertilisation to the early cleavage stages in the domestic fowl (Gallus domesticus)

The changes in nuclear morphology from fertilisation to the 16-blastomere stage of development in the domestic fowl were examined in sections of the germinal disc stained with DAPI (4',6'-diamidino-2-phenylindole) or with the Feulgen technique. By one hour after the estimated time of ovulation, the second meiotic division of the ovum was completed and the spermatozoal heads (3-9) in the germinal disc had transformed into pronuclei. During the following two hours all the pronuclei enlarged, and two of them became juxtaposed. Mitotic figures and large pronuclei were observed at 4 hours. The zygote nucleus went through 3-4 division cycles in synchrony. The supernumerary male nuclei divided once, at most, and all showed evidence of degeneration by the 4-blastomere stage, at about five hours. Therefore, the nuclei destined to form the future chick embryo follow a pattern of behaviour during fertilisation and early cleavage similar to that of animals in general.

Animals↗
PubMed1982

Isolation, culture, and preliminary characterization of mucin-producing cells from trachea of the domestic fowl.

Primary cell cultures enriched in mucin-producing cells and basal cells were established from the trachea of the domestic fowl. Epithelial cells were selectively removed from the trachea after incubation in 0.1% pronase/0.1% EDTA in Moscona's saline. The majority of the ciliated cells were removed during the initial 30 minutes of incubation. After 50 minutes of incubation, aggregates of mucin-producing cells and basal cells were removed in large numbers. The cellular aggregates rapidly attached to a collagen-coated substratum and the cells spread out on the culture surface. The mucin-producing cells retained their AB/PAS-reactive secretory granules. The basal cells replicated and as the culture approached confluency, these cells developed a fine dusting of AB/PAS-reactive material; later, larger secretory granules appeared in the cells. These observations suggest that mucin-producing cells are capable of retaining their AB/PAS-reactive secretory products in primary culture and that basal cells are capable of differentiating into mucin-producing cells in vitro.

Animals↗
PubMed1980

The preoptic area of the domestic fowl. II. Ultrastructure of the medial preoptic area.

Numerous secretory parvocellular perikarya were found in the preoptic region of the domestic fowl (Gallus gallus). The dense-core secretory vesicles belong to two categories: vesicles with a diameter of (i)80-90 nm and (ii) 110-140 nm. Scattered magnocellular elements display larger dense-core granules. The parvocellular neurons form unit-like clusters, showing also zones of direct apposition of neuronal membranes. The surrounding neuropil is rich in synaptic structures, formed by at least three types of axon terminals, distinguishable on the basis of vesicular morphology. These observations confirm the findings in other avian species. The hypothetical function of this system of peptidergic neurons in the rostral hypothalamus of birds is discussed.

Animals↗
PubMed1980

Ultrastructural alterations of the pancreatic D cell in the domestic fowl following vagotomy.

In an attempt to determine the neural control of pancreatic D cells, the pancreatic islets of the domestic fowl were examined electron microscopically from 1 to 28 days after abdominal vagotomy. Exocytotic release of many secretory granules from D cells occurred one day after vagotomy. Rough endoplasmic reticulum developed and formed an arrangement of concentric whorls in the cytoplasm of D cells after axotomy. The altered D cells were also characterized by the occurrence of many peculiar dense bodies in the apical cytoplasm at all time periods studied. These bodies varied in shape and size, containing several round vesicles. The D cells were extensively depleted of granules after the longer time periods following vagotomy. The present results provide new morphological evidence for the vagus-nerve control of D cells, which may regulate the activity of islet cells.

Animals↗
PubMed1983

Pharmacological studies on the noradrenergic control of luteinizing hormone secretion in the domestic fowl.

A neuropharmacological approach was utilized in order to investigate catecholaminergic involvement in the control of LH secretion in the domestic fowl. Inhibition of catecholamine synthesis by alpha-methyl-p-tyrosine (alpha Mpt) at several doses was accompanied by significant reductions in the circulating LH concentration of 6-week-old male cockerels. Plasma LH was similarly depressed following the selective inhibition of NE synthesis by either diethyldithiocarbamate (DDC) or FLA 63. Blockade of alpha 1-adrenergic receptors with phenoxybenzamine was consistently associated with precipitous declines in plasma LH concentrations. Stimulation of alpha-adrenergic receptors by phenylephrine and clonidine elevated circulating LH levels. Activation of the dopaminergic system by apomorphine depressed LH release. However, pimozide was without effect. These data suggest that norepinephrine is involved in the stimulation of LH release, while dopamine may exert an inhibitory influence. Evidence of some stimulatory beta-adrenergic effect is also described.

Animals↗