Summary
Dog saphenous vein strips were incubated with 1.4 μmol/l 3H-(-)-noradrenaline for 60 min, after inhibition of the noradrenaline-metabolizing enzymes and of extraneuronal uptake. At the end of the incubation period the strips were perifused for 150 min; cocaine (10 μmol/l) was added to the perifusion fluid from t=75 min onwards. In some experiments either phentolamine (10 μmol/l) or clonidine (0.1 μmol/l) was also added at this time. Some strips were subjected to electrical stimulation from t=100 to 150 min of perifusion (t=0 being the start of perifusion), with frequencies ranging from 0.5 to 13.5 Hz. A compartmental analysis of spontaneous or electrically-induced efflux of 3H-noradrenaline was made. The spontaneous efflux had a long half time (t/2=124 min) and most of the 3H-noradrenaline which had accumulated in the strips did not participate in the efflux (“bound fraction”, representing 90% of tissue activity at t=100 min of perifusion). Neither phentolamine nor clonidine modified the half time or the “bound fraction” observed for spontaneous efflux. Electrical stimulation (>0.5 Hz) mobilized only one compartment of noradrenaline, which represented about 50% of the noradrenaline accumulated in the strips. The half time of 3H-efflux induced by electrical stimulation decreased when the frequency increased from 0.5 Hz up to 13.5 Hz. Phentolamine increased the rate of efflux for all frequencies of stimulation and decreased the half time of efflux. However, the releasable pool of noradrenaline was only increased by phentolamine at 0.5 Hz, but not at higher frequencies. Clonidine was used only at two frequencies of stimulation, 1.5 and 4.5 Hz. For the low frequency clonidine decreased the releasable pool, but no change was observed at 4.5 Hz.
The results support the view that there is a norarenaline pool which is resistant to electrical stimulation and that its magnitude is not dependent on the activity of presynaptic α-adrenoceptors.
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References
Brandão F (1977) Inactivation of norepinephrine in an isolated vein. J Pharmacol Exp Ther 203:23–29
Brandão F, Rodrigues-Pereira E, Monteiro JG, Osswald W (1980) Characteristics of tyramine induced release of noradrenaline: mode of action of tyramine and metabolic fate of the transmitter. Naunyn-Schmiedeberg's Arch Pharmacol 311:9–15
Brandão F, Rodrigues-Pereira E, Monteiro JG, Davidson R (1981) A kinetic study of the release of noradrenaline by tyramine. Naunyn-Schmiedeberg's Arch Pharmacol 318:83–87
Chang CC, Chang JC (1965) A change in the subcellular distribution of noradrenaline in the rat isolated vas deferens effected by nerve stimulation. Br J Pharmacol 25:758–762
Davies BN (1963) Effect of prolonged activity on the release of the chemical transmitter at postganglionic sympathetic nerve endings. J Physiol (Lond) 167:52P
Eckert E, Henseling M, Gescher A, Trendelenburg U (1976) Stereoselectivity of the distribution of labelled noradrenaline in rabbit aortic strips after inhibition of the noradrenalinemetabolizing enzymes. Naunyn-Schmiedeberg's Arch Pharmacol 292:201–229
Farnebo L-O, Lidbrink P (1971) Synthesis of noradrenaline in isolated rat iris during field stimulation. Acta Physiol Scand Suppl 371:29–34
Guimarães S, Osswald W (1969) Adrenergic receptors in the veins of the dog. Eur J Pharmacol 5:133–140
Guimarães S, Brandão F, Paiva MQ (1978) A study of the adrenoceptor-mediated feedback mechanisms by using adrenaline as a false transmitter. Naunyn-Schmiedeberg's Arch Pharmacol 305:185–188
Henseling M, Eckert E, Trendelenburg U (1976) The distribution of 3H-(±)noradrenaline in rabbit aortic strips after inhibition of the noradrenaline-metabolizing enzymes. Naunyn-Schmiedeberg's Arch Pharmacol 292:205–217
Hughes J (1973) Differential labelling of intraneuronal noradrenaline stores with different concentration of (-)-3H-noradrenaline. Br J Pharmacol 47:428–430
Huković S, Muscholl E (1962) Die Noadrenalin-Abgabe aus dem isolierten Kaninchenherzen bei sympathischer Nervenreizung und ihre pharmakologische Beeinflussung. Naunyn-Schmiedeberg's Arch Exp Path Pharmak 244:81–96
Kirpekar SM, Prat JC, Puig M, Wakade AR (1972) Modification of the evoked release of noradrenaline from the perfused cat spleen by various ions and agents. J Physiol (Lond) 221:601–615
Kopin IJ, Breese GR, Krauss KR, Weise VK (1968) Selective release of newly synthesized norepinephrine from the cat spleen during sympathetic nerve stimulation. J Pharmacol Exp Ther 161:271–278
Langer SZ (1977) Presynaptic receptors and their role in the regulation of transmitter release. Br J Pharmacol 60:481–497
Langer SZ (1980) Presynaptic regulation of the release of catecholamines. Pharmacol Rev 32:337–362
Lorenz RR, Vanhoutte PM (1975) Inhibition of adrenergic neurotransmission in isolated veins of the dog by potassium ions. J Physiol (Lond) 246:479–500
Lorenz RR, Vanhoutte PM, Shepherd JT (1979) Interaction between neuronal amine uptake and prejunctional alpha-adrenergic receptor activation in smooth muscle from canine blood vessels and spleen. Blood Vessels 16:113–125
McGrath MA (1977) 5-Hydroxytryptamine and neurotransmitter release in canine blood vessels. Circ Res 41:428–435
Muscholl E, Spira F-J (1982) Effect of dl-α-monofluoromethyldopa on the kinetics of noradrenaline and dopamine β-hydroxylase release from the perfused heart. Br J Pharmacol 77:535P
Rapoport RM, Takimoto GS, Cho AK (1981) Compartmental analysis of tyramine-induced norepinephrine depletion. Pharmacology 22:235–242
Starke K (1977) Regulation of noradrenaline release by presynaptic receptors systems. Rev Physiol Biochem Pharmacol 77:1–124
Starke K (1981) Presynaptic receptors. Ann Rev Pharmacol Toxicol 21:7–30
Starke K, Montel H, Gayk W, Merker R (1974) Comparison of the effect of clonidine on pre- and postsynaptic adrenoceptors in the rabbit pulmonary artery. Naunyn-Schmiedeberg's Arch Pharmacol 285:133–150
Stjärne L, Wennmalm A (1970) Preferential secretion of newly formed noradrenaline in the perfused rabbit heart. Acta Physiol Scand 80:428–429
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Results presented in part to the 13th Annual Meeting of the Portuguese Pharmacological Society (Porto, December 1982) and to the 5th Meeting on Adrenergic Mechanisms (Porto, October 1983)
Work supported by a grant from Instituto Nacional de Investigação Científica (FmPl)
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Brandão, F., Davidson, R. & Monterio, J.G. A kinetic study of the release of noradrenaline by electrical stimulation: influence of presynaptic α-adrenoceptors. Naunyn-Schmiedeberg's Arch. Pharmacol. 328, 248–252 (1985). https://doi.org/10.1007/BF00515549
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DOI: https://doi.org/10.1007/BF00515549