The influence of 6-OHDA on hypothermia produced by intrahypothalamically-injected carbachol in the pigeon

Summary The involvement of the noradrenergic system in hypothermia induced by intrahypothalamically-injected carbachol (CCh) was studied by depleting hypothalamic noradrenaline (NA) with the catecholamine neurotoxin 6-hydroxydopamine (6-OHDA) and repeating the CCh injections after 6-OHDA treatment. The results suggest that noradrenergic neurons may be involved in hypothermia produced by CCh in the pigeon.     

Effect of repeated electroconvulsive shock on plasma noradrenaline and adrenaline in man

Summary The concentration of noradrenaline (NA) and of adrenaline (A) in plasma was measured before and 3, 30 and 60 min after single and repeated electroconvulsive shocks (ECS). Single ECS resulted in an activation of the sympathoadrenal medullary system; however, after the treatment had been repeated 4 times there was evidence of a diminished response of the peripheral sympathetic nervous system in comparison to the response to the first ECS.     

Determination of plasma catecholamines in conscious normotensive and hypertensive (sodium and desoxycorticosterone) rats]

Plasma noradrenaline and adrenaline were measured in conscious Rats on 50 microliter samples by a radiometric technique. In normotensive Rats a moderate haemorrhage increased catecholamine levels. In Rats rendered hypertensive by salt loading and by desoxycorticosterone treatment noradrenaline levels were increased.     

In vivo degradation of noradrenaline by MAO A in locus coeruleus of the rat

Depletion of noradrenaline in locus coeruleus neurons after reserpinization was prevented by clorgyline, a selective inhibitor of MAO A, but not by deprenyl, a selective inhibitor of MAO B. Only MAO A is therefore responsible for the degradation of homoneuronal noradrenaline in locus coeruleus nerve cells.     

Differential sensitivity of pinna reflex and esophageal temperature to clonidine in mice depleted of central noradrenaline by DSP-4

Mice injected with DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine], a selective noradrenergic neurotoxin, had marked depletions of central noradrenaline and an attenuated post-decapitation reflex. DSP-4-treated mice exhibited an increased sensitivity to the alpha 2-adrenoceptor agonist clonidine as measured by inhibition of the pinna reflex, but normal sensitivity as measured by hypothermia. This differential sensitivity may reflect the presence of supersensitive postsynaptic alpha 2-adrenoceptors in some, but not all, CNS regions after DSP-4 treatment.     

Wirkungsverstärkung von Adrenalin und Noradrenalin durch Azetylcholin am isolierten Irisdilatator des Kaninchens

Summary Radial strips of the isolated iris of rabbits were suspended in streaming Tyrode's solution and their contractions were registered isometrically. The contractions produced by adrenaline or noradrenaline were increased after the administration of eserine or neostigmine. Acetylcholine in a concentration 5.10^–7–5.10^–6 M enhanced the effect of adrenaline and noradrenaline on both, the normal and the chronically denervated dilator muscle. Acetylcholine did not enhance the contractions by adrenaline and noradrenaline in the presence of atropine. Choline in a concentration of 5.10^–6 M had no effect whereas concentrations of 5.10^–5 M were slightly effective.     

Critical comment on the "trophic" influence of the effector organ on the sympathetic nerves of the male sex accessories of the guinea-pig.

There is no absolute parallelism between organ noradrenaline content and organ weight in the male sex accessories during normal development or following regression after castration.     

Critical comment on the ‘Trophic’ influence of the effector organ on the sympathetic nerves of the male sex accessories of the guinea-pig

Summary There is no absolute parallelism between organ noradrenaline content and organ weight in the male sex accessories during normal development or following regression after castration.     

Die Wirkung von Harmalin auf die Konzentration von Noradrenalin und Adrenalin im Herzen

Summary A single injection of harmaline increases the noradrenaline and adrenaline concentration in the rat heart. The maximum effect is obtained after about 40 min.     

Leukocyte mobilization from the guinea pig spleen by muscarinic cholinergic stimulation

Important interactions between the immune system and the nervous and endocrine systems have become increasingly accepted. The present results demonstrate that the cholinergic agonist carbacholine greatly increased the number of granulocytes and lymphocytes in the splenic venous blood, but not arterial blood, shortly after administration to guinea pigs. The effect was largely blocked by pretreatment with atropine. In contrast, animals treated with indomethacin had a decreased number of leukocytes in both splenic venous and arterial blood. A decrease in relative splenic weight due to carbacholine treatment was also blocked by atropine. However, cholinergic leukocyte mobilization, or that previously observed after adrenergic stimulation, may not be caused by capsule contraction since it is not accompanied by mobilization of erythrocytes. Furthermore, indomethacin, which potentiates the response of splenic smooth muscle to adrenergic stimuli, blocked the effect of noradrenaline (NA) on leukocyte mobilization.     

Central effect of 5,8,11,14-eicosatetraenoic acid (arachidonic acid) on the temperature in the conscious rabbit

Summary Hyperthermia induced by arachidonic acid in rabbit was attenuated by phenoxybenzamine, cyproheptadine and indomethacin. The reduction in arachidonic acid hyperthermia, after 6-OH-DA and the failure of PCPA to reduce this rise, indicates the involvement of noradrenaline in arachidonic acid hyperthermia.     

Leukocyte mobilization from the guinea pig spleen by muscarinic cholinergic stimulation

Important interactions between the immune system and the nervous and endocrine systems have become increasingly accepted. The present results demonstrate that the cholinergic agonist carbacholine greatly increased the number of granulocytes and lymphocytes in the splenic venous blood, but not arterial blood, shortly after administration to guinea pigs. The effect was largely blocked by pretreatment with atropine. In contrast, animals treated with indomethacin had a decreased number of leukocytes in both splenic venous and arterial blood. A decrease in relative splenic weight due to carbacholine treatment was also blocked by atropine. However, cholinergic leukocyte mobilization, or that previously observed after adrenergic stimulation, may not be caused by capsule contraction since it is not accompanied by mobilization of erythrocytes. Furthermore, indomethacin, which potentiates the response of splenic smooth muscle to adrenergic stimuli, blocked the effect of noradrenaline (NA) on leukocyte mobilization.     

Central effect of 5,8,11,14-eicosatetraenoic acid (arachidonic acid) on the temperature in the conscious rabbit

Hyperthermia induced by arachidonic acid in rabbit was attenuated by phenoxybenzamine, cyproheptadine and indomethacin. The reduction in arachidonic acid hyperthermia, after 6-OH-DA and the failure of PCPA to reduce this rise, indicates the involvement of noradrenaline in arachidonic acid hyperthermia.     

The role of sialic acid in 5-HT binding to synaptic membranes.

The high affinity binding of [14C]5-HT to nerve ending membranes isolated from rat brain is not affected by neuraminidase treatment. The specificity of ligand receptor interaction was demonstrated by displacement studies with tryptamine derivatives, noradrenaline, and acetylcholine.     

The effects of thermogenic agents on hindlimb oxygen consumption in the dog: ICI D7114 and noradrenaline

The thermogenic action of beta-adrenoceptor agonists may be due, in part, to increased metabolism in skeletal muscle. Previous results suggest that vasoconstriction is also necessary, and that the effect can be blocked by vasodilators. Both noradrenaline and the beta-3 agonist, ICI D7114, were studied using two dog hindlimb protocols. During constant perfusion conditions, ICI D7114 caused a significant increase in hindlimb oxygen consumption although it is a vasodilator. Noradrenaline resulted in a smaller rise in oxygen consumption, and produced a marked vasoconstriction. Both noradrenaline and ICI D7114 resulted in decreased oxygen consumption when the blood flow was allowed to vary in response to the drug treatment. The results suggest that changes in tissue oxygen consumption caused by beta-agonists are not related to vasomotion.     

Effect of starvation on the blood ofOphiocephalus punctatus (Bloch)

Summary During starvation the values of RBC, WBC counts, Hb content and packed cell volume declined. After 15, 21 and 27 days of starvation little fluctuation was noted but major fluctuation was recorded after 33 days of starvation in all the above parameters.Thanks are due to CSIR, New Delhi, for financial assistance.     

Acute cold exposure increases the glucagon sensitivity of thermogenic metabolism in the rat

Administration of glucagon to rats at 25 degrees C had no effect upon their VO2, while administration of noradrenaline or noradrenaline plus glucagon raised the VO2. At 5 degrees C, noradrenaline had no effect upon the cold-enhanced VO2, while glucagon caused a rise of 13.7%, implying increased glucagon sensitivity at 5 degrees C. The glucagon-induced enhancement of VO2 was abolished by concurrent administration of noradrenaline.     

Acute cold exposure increases the glucagon sensitivity of thermogenic metabolism in the rat

Summary Administration of glucagon to rats at 25°C had no effect upon their VO₂ while administration of noradrenaline or noradrenaline plus glucagon raised the VO₂-At 5°C, noradrenaline had no effect upon the cold-enhanced VO₂, while glucagon caused a rise of 13.7% implying increased glucagon sensitivity at 5°C. The glucagon-induced enhancement of VO₂ was abolished by concurrent administration of noradrenaline.     

Stress-induced increase in noradrenaline release in the rat hypothalamus assessed by intracranial microdialysis

The hypothalamic microdialysis of conscious rats was used to investigate the effects of immobilization stress (20 min) on extracellular noradrenaline (NA) levels. The stress significantly increased NA levels relative to basal efflux by 106% and this elevation continued for 40 min after release from stress.     

Stress-induced increase in noradrenaline release in the rat hypothalamus assessed by intracranial microdialysis

Summary The hypothalamic microdialysis of conscious rats was used to investigate the effects of immobilization stress (20 min) on extracellular noradrenaline(NA) levels. The stress significantly increased NA levels relative to basal efflux by 106% and this elevation continued for 40 min after release from stress.