Some aspects of thermoregulation in the adult Japanese quail (Coturnix coturnix Japonica)

The role of beta-adrenergic receptors in the cutaneous water evaporation mechanism in the heat-acclimated pigeon (Columba livia)

The effects of selective and non-selective beta-adrenergic agents on cutaneous water evaporation (CWE) were studied in hand-reared rock pigeons (Columba livia). CWE was measured by the vapor diffusive resistance method, using a transient porometer. Intramuscular and subcutaneous injections of a non-selective beta-adrenergic antagonist (propranolol) or a selective beta(2)-adrenergic antagonist (ICI-118551) to heat-acclimated (HAc) pigeons at ambient temperature (T(a)) of 24 degrees C resulted in intensive CWE. The CWE values that were triggered by propranolol and ICI-118551 (18.59+/-0.73 and 16.48+/-0.70 mg cm(-2) h(-1), respectively) were close to those induced by heat exposure (17.62+/-1.40 mg cm(-2) h(-1)). Subcutaneous administration of propranolol produced local response. Intramuscular injection of salbutamol (selective beta(2)-adrenergic agonist) to HAc pigeons drastically diminished CWE induced by either propranolol, metoprolol or heat exposure. Such manipulations also enhanced panting at relatively low T(a)s (42 degrees C). The inhibition of beta(1)-adrenergic receptors by metoprolol increased CWE, while inhibition by atenolol produced no change from basal values. This difference may be attributed to their distinctive nature in penetrating the blood-brain barrier. Our findings indicate a regulatory pathway for CWE consisting of both beta(1)- and beta(2)-adrenergic receptors. We suggest that the beta(1)-adrenergic effect is restricted mainly to the CNS, while the beta(2)-adrenergic effect takes place at the effector level. We postulate this level to be either the cutaneous microvasculature or the epidermal layer.

The behavior of the Japanese or domestic quail Coturnix japonica

This paper reviews the literature pertaining to the behavior of the Japanese or domestic quail Coturnix japonica. Details are given of the classification, characteristics, domestication and the economic and research potential of the species. Further sections deal with sensation and perception (including taste and smell, vision and hearing), maintenance behavior (including feeding and drinking, dust bathing and thermoregulation), development and aging (including vocalization, filial imprinting, sexual imprinting, fear and avoidance responses, sexual maturation and aging), adult learning (including habituation, instrumental conditioning, Pavlovian conditioning and observational learning), photoperiodism, reproductive behavior (including courtship and mating, hormonal control and ontogeny of sexual differentiation, and male and female sexual behavior), parental behavior (including nest-site selection and nest building, incubation behavior and its hormonal control, and hen-chick relationships), and aggressive behavior and dominance (including agonistic behavior and the hormonal control of aggressive behavior).

Influence of corticosterone infusion on plasma levels of catecholamines, thyroid hormones, and certain metabolites in laying hens

Corticosterone was infused continuously through subcutaneously implanted mini-osmotic pumps into laying White Leghorn hens at the rate of 30 micrograms/hr for 14 or 28 days. In both groups receiving corticosterone, plasma levels of glucose and triglycerides were not altered significantly. Circulating levels of cholesterol and free fatty acids increased significantly following both 14 and 28-day infusions of the hormone. Corticosterone treatment for 28 days produced significant increases in plasma levels of thyroxine (T4) and triiodothyronine (T3). However, following the 14-day corticosterone infusion, only T3 showed significant increase. The T3:T4 ratio in both groups of corticosterone-infused hens was significantly higher than in control hens. The concentration of plasma epinephrine showed no significant response to corticosterone treatment, while norepinephrine increased significantly following both periods of treatment.

Effect of vagotomy on plasma levels of growth hormone, free fatty acids and glucose in the pigeon

Plasma levels of growth hormone (GH), free fatty acids (FFA) and glucose were measured in vagotomized (VgX) and sham-operated (VgS) control pigeons. In VgX pigeons, GH level was significantly lower whereas FFA and glucose levels were higher than in VgS pigeons. The depression in GH level in VgX pigeons has been attributed to the significantly high levels of norepinephrine (NE) and corticosterone in these Birds. The higher plasma FFA concentration in VgX pigeons was therefore due to adipokinetic hormonal action other than of GH. It has been suggested that the adrenocorticotrophic hormone (ACTH) and/or NE could have produced the increase in plasma FFA in VgX pigeons. The pronounced hyperglycemia seen in VgX pigeons has been attributed to catecholamine action in the absence of the vagal tone.

Changes in body temperature after administration of adrenergic and serotonergic agents and related drugs including antidepressants

This survey, the third in a series, presents extensive tabulations of literature, primarily since 1965, on thermoregulatory effects of adrenergic and serotonergic agonists and their antagonists including ergot alkaloids, amphetamines, tryptamines, monoamine oxidase inhibitors, tricyclic and other antidepressants, a variety of other agents which alter presynaptic aminergic mechanisms including reserpine, 6-hydroxydopamine, p-chlorophenylalanine, alpha-methyltyrosines, cocaine, guanethidine and bretylium. The information listed includes the species used, route of administration and dose of drug, the environmental temperature at which the experiments were performed, the number of tests, the direction and magnitude of body temperature change and remarks on the presence of special conditions, such as age or lesions, or on the influence of other drugs, such as antagonists, on the response to the primary drug.

Short-term stressor effects of propranolol

1. The effects of propranolol (10 mg/kg) on plasma cholesterol, glucose, corticosterone and free fatty acids, on adrenal mass and cholesterol content and on body temperature were determined over a 24-h period in 3-week-old Light Sussex chicks. 2. Changes in plasma cholesterol were equivocal, though there was perhaps a trend towards hypercholesteraemia. 3. Birds became hypoglycaemic within an hour but were hyperglycaemic between 2 and 4 h. At 24 h they were normoglycaemic. 4. Plasma corticosterone was increased markedly at 1 h but was decreased compared with the control at 2 h ( P < 0.01). Thereafter the concentration was in the normal range. 5. There was an enhanced hyperlipacidaemia in the treated birds after 1 h. 6. Adrenal cholesterol stores were decreased by 10% at 4 h but were unaffected at all other times. 7. Colonic temperature decreased by 1x6 degrees C after 2 h but was normal by 4 h. 8. It is concluded that propranolol has mild stressor activity which is lost within 24 h.

Changes in muscle, liver, and plasma free fatty acid levels in the pigeon on acute exposure to cold

Adult pigeons were subjected to acute cold exposure (-25 degrees C; 30 min). Fully-plumed birds, showed a pronounced increase in the level of FFA in the blood, but not in the liver or muscle. Partially-defeathered (dorsum and pectoral regions) birds, likewise, showed a marked increase in plasma FFA level but failed to indicate any change in FFA levels in the liver or the muscle. It is concluded that even if the mobilized FFA may have supported calorigenic processes in the normothermic cold-exposed pigeon, lipid reserves are unlikely to have served as a significant source of energy for thermogenic functions in the hypothermic (defeathered) bird.

Effect of adrenergic blocing agents on peripheral noradrenaline induced thermoregulatory responses in the pigeon at heat

1. The hyperthermic effect of intramuscular NA at 32 degrees C was abolished by propranolol but not by phentolamine preinjection. 2. The lack of hyperthermic response was at least partly due to the blocking effect of propranolol on beta-receptor mediated in heart rate. 3. After NA the respiratory rate was gradually increased in birds preinjected either with propranolol or with phentolamine.

Changes in blood glucose, blood and muscle lactate,and plasma lactic dehydrogenase levels in the pigeon on acute exposure to cold

Adult pigeons were subjected to acute cold exposure (-25 degrees C; 30 min) after which the levels of blood glucose, blood and muscle lactate and plasma lactic dehydrogenase were measured. Partially defeathered (dorsum and pectoral regions) birds, following exposure to cold, showed marked reduction in blood glucose and blood and muscle (pectoralis) lactate. Fully plumed birds, in contrast, showed no significant reduction in body temperature or blood glucose and only moderately reduced lactate levels indicating the effectiveness of the insulative feather coat in maintaining thermal and metabolic homeostasis. The partially-defeathered pigeons exposed to cold showed a two-to-three-fold increase in plasma lactic dehydrogenase activity, which may reflect a molecular adaptation in their calorigenic response to cold.