Adrenergic Neurone Blocking Agents

Adrenergic neurone blocking agents usually interfere with postganglionic sympathetic nervous transmission but they do not exert any effect on the parasympathetic nervous system. 

The following two compounds belonging to this category shall be discussed, namely Guanethidine monosulphate Bethanidine sulphate  

Alkylation of saturated azocine with chloroacetonitrile yields an intermediate and a mole of hydrogen chloride gets eliminated. Catalytic reduction of the intermediate affords the diamine. The 

It is an antihypertensive agent which is frequently employed in the treatment of moderate and severe hypertension, or for mild hypertension. It has a rather slow onset of action, the full effect may range from several hours to 2 or 3 days, and its duration of action may extend from 4 or more days. 

Dose Usual, initial 10 to 20 mg per day usual maintenance dose 30 to 100 mg per day as a single dose hut up to 300 mg daily may be given. 

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The answers are 321-cT 322-e, 323-i. (Hardman, pp 238-239, 791.) Reserpine is an adrenergic neuronal blocking agent that causes depletion of central and peripheral stores of NE and dopamine Reserpine acts by irreversibly inhibiting the magnesium-dependent ATP transport process that functions as a carrier for biogenic amines from the cytoplasm... 

An excellent review of the pharmacological actions of adrenergic neurone blocking agents has been given by Boura and Green [10]. The biochemistry of guanethidine itself has been reviewed by Furst [11], with particular emphasis on tissue distribution and metabolism consequently these two topics are not discussed in detail. 

Quaternary ammonium analogues of the 5-chloro and 5- and 6-methyl substituted guanidines were inactive as adrenergic neurone blocking agents... 

The bicyclic amidoximes (LXIV) and (LXV) cause a reduction in blood pressure in various animal species, but apparently they are not adrenergic neurone blocking agents [270]. The activity of (LXIV)i thought to be mainly due to catecholamine release and subsequent depletion, whilst the action of (LXV) involves blockade at a-receptors [270]. 

The dimethylguanidine (LXVII, R = R = Me) causes vasodilatation but lowers blood pressure as a consequence of adrenergic neurone blockade [278]. Apparently, the related imidazoline (LXVIII) is not an adrenergic neurone blocking agent but a hypotensive, which acts by vasodilatation and blockade of a-receptors [279]. 

The tetrahydrobenzazepine (LXIX) related to debrisoquine (LXVII) is reported to be a potent adrenergic neurone blocking agent (three-fifths as potent as guanethidine in anaesthetized cats) [280]. Marked sympathomimetic activity is not associated with (LXIX) and in this respect it is similar to the hexahydrobenzazo-... 

Tricyclic antidepressants potentiate the pressor effects of directly acting sympathomimetic amines, such as adrenaline (epinephrine) or noradrenaline (norepinephrine), to cause hypertension. Small amounts of these, such as may be present in local anaesthetic solutions, can be dangerous. Tricyclic antidepressants will inhibit the antihypertensive effects of the older anti hypertensive drugs, such as adrenergic neurone-blocking agents, e.g. guanethidine, a-methyl-DOPA, and clonidine. 

The exact mechanism of this peripheral adrenergic neuron blocking agent is not well defined. Reserpine administration results in depleted stores of norepinephrine, dopamine, and serotonin in multiple organs. The decreased peripheral resistance and cardiac output that results is manifested as a decrease in blood pressure. A central nervous system (CNS) effect may also play a role in decreasing blood... 

Bretylate > bretylium tosylate. bretylium tosylate [ban, inn, usan] (BretyloP Bretylate ) is a quaternary ammonium ANTISYMPATHETIC and ADRENERGIC NEURON BLOCKING AGENT used as an ANTIHYPERTENSIVE and (class III) ANTI ARRHYTHMIC. Bretylol bretylium tosylate. 

Activities and sites of antinociceptive action of morphine-like analgesics. 6, 79 Adrenergic neurone blocking agents, 1, 161 Advances in penicillin research, 7, 1... 

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