Presynaptic α-Adrenoceptor Control of Transmitter Release from Vascular Sympathetic Neurones in Vitro

Nedergaard, Ove A.

doi:10.1007/978-3-642-71313-2_3

Cited by 6 publications

(4 citation statements)

References 27 publications

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“…mitter had been inhibited by cocaine and corticosterone, respectively. This is supported by the observation that rauwolscine in the same concentration range enhanced the stimulation-evoked release of ['H]-NA release in the rabbit pulmonary artery (Weitzell et al, 1979;Nedergaard, 1986). Chlorpromazine reduced the accumulation of 'H by aorta preloaded with ['H]-NA.…”

Section: Discussionmentioning

confidence: 61%

Effect of chlorpromazine on sympathetic neuroeffector transmission in the rabbit isolated pulmonary artery and aorta

Nedergaard¹,

Abrahamsen²

1988

British J Pharmacology

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The effects of chlorpromazine on sympathetic neuroeffector transmission have been studied in the rabbit isolated pulmonary artery and aorta. Chlorpromazine (10−8‐10−5 m), prazosin (10−9‐10−7 m) and phentolamine (3 × 10−8‐3 × 10−5 m) decreased the contractions of pulmonary artery evoked by electrical field stimulation (150 pulses; 3 Hz). The rank order of inhibitory potency (ID50) was prazosin > chlorpromazine > phentolamine. Rauwolscine (3 × 10−9 m‐4 × 10−6 m) enhanced the neurogenic response by up to 201%. However, higher concentrations (6 × 10−6‐3 × 10−5 m) reduced the contractions evoked by transmural stimulation. The inhibitory effect of prazosin (10−6 m) was reversible, while that of chlorpromazine (10−8 m) was not. Chlorpromazine (10−8‐10−4 m), desmethylimipramine (3 × 10−9‐10−5 m), cocaine (10−7‐3 × 10−4 m) and phentolamine (10−5‐3 × 10−4 m) reduced the accumulation of [3H]‐noradrenaline ([3H]‐NA, 10−8 m) by aorta. The rank order of inhibitory potency (ID50) was: desmethylimipramine > chlorpromazine > cocaine > phentolamine. Prazosin (10−7‐10−5 m) and rauwolscine (10−8‐10−4 m) did not reduce [3H]‐NA accumulation. Chlorpromazine (10−8‐10−6 m) and prazosin (3 × 10−9‐10−7 m) antagonized the contractions of aorta evoked by exogenous noradrenaline (10−9‐3 × 10−4 m) and phenylephrine (10−9‐3 × 10−3 m). The pA2 values for chlorpromazine on the α1‐adrenoceptors were 8.24 (noradrenaline) and 8.27 (phenylephrine). The corresponding values for prazosin were 8.64 and 8.57, respectively. It is concluded that chlorpromazine and prazosin are potent inhibitors of postsynaptic α1‐ adrenoceptors. Chlorpromazine and phentolamine, unlike prazosin and rauwolscine, are also inhibitors of Uptake.

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Section: Discussionmentioning

confidence: 61%

Effect of chlorpromazine on sympathetic neuroeffector transmission in the rabbit isolated pulmonary artery and aorta

Nedergaard¹,

Abrahamsen²

1988

British J Pharmacology

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“…This would probably be more so at high concentrations of reboxetine. The ability of cocaine to modulate the depolarizationevoked norepinephrine release via prejunctional ␣ 2 -adrenoceptors depended inter alia on the concentration of cocaine, the stimulation intensity (frequency and length of pulse train) and the geometry of the junctional cleft (Nedergaard, 1986). This conclusion was based on a study of the interaction between cocaine and ␣ 2 -adrenoceptor antagonists.…”

Section: Discussionmentioning

confidence: 99%

“…A similar interaction study using reboxetine instead of cocaine remains to be done. Inhibition of prejunctional ␣ 2 -adrenoceptors located on vascular sympathetic neurons by ␣ 2 -adrenoceptor antagonists, such as e.g., rauwolscine, enhances the stimulation-evoked [ 3 H]norepinephrine release (Nedergaard, 1986). Because reboxetine has poor affinity to ␣ 2 -adrenoceptors (Wong et al, 2000), it is most unlikely that the reboxetine-evoked enhancement of [ 3 H]norepinephrine release (Fig.…”

Section: Discussionmentioning

confidence: 99%

Effects of Reboxetine on Sympathetic Neuroeffector Transmission in Rabbit Carotid Artery

Rasmussen

Nedergaard

2003

J Pharmacol Exp Ther

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“…There is overwhelming documentation for the view that activation of presynaptic alphaa-adrenoceptors initiates a negative feedback system which results in inhibition of transmitter release (16,17). However, this so-called autoreceptor theory has been challenged (1 8).…”

Section: Modulation Of Catecholamine Releasementioning

confidence: 99%

Catecholamines: Regulation, Release and Inactivation

Nedergaard¹

1988

Pharmacology & Toxicology

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Presynaptic α-Adrenoceptor Control of Transmitter Release from Vascular Sympathetic Neurones in Vitro

Cited by 6 publications

References 27 publications

Effect of chlorpromazine on sympathetic neuroeffector transmission in the rabbit isolated pulmonary artery and aorta

Effect of chlorpromazine on sympathetic neuroeffector transmission in the rabbit isolated pulmonary artery and aorta

Effects of Reboxetine on Sympathetic Neuroeffector Transmission in Rabbit Carotid Artery

Catecholamines: Regulation, Release and Inactivation

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