Effect of Guanethidine in Revealing Cholinergic Sympathetic Fibres

Day, Michael; Rand, M. J.

doi:10.1111/j.1476-5381.1961.tb01285.x

Cited by 46 publications

(30 citation statements)

References 33 publications

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“…The present results are consistent with the 'on' contractions being mediated entirely via enteric neurons, because they were completely blocked by hexamethonium. This has been previously described for longitudinal muscle contractions evoked by MN stimulation (Day & Rand, 1961;De Luca & Rand, 1990). This effect of hexamethonium suggests that the extrinsic primary afferents act on interneurons or intrinsic sensory neurons, rather than directly on excitatory motor neurons, which is consistent with an earlier observation that MN stimulation depolarizes some intrinsic sensory neurons in the guinea-pig ileum (Takaki & Nakayama, 1988).…”

Section: Excitatory Effects Of Mn Stimulationsupporting

confidence: 90%

Role of α₂‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum

Stebbing

Johnson

Vremec

et al. 2001

The Journal of Physiology

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1. Sympathetic regulation of the motility of guinea-pig ileum was investigated using mesenteric nerve (MN) stimulation to inhibit motility reflexes, in vitro.2. Transmural electrical stimulation (5 Hz, 1 s) in intact intestinal segments, or inflation of a balloon against the mucosa in opened segments, evoked contractions of the circular and longitudinal muscles oral to the stimulus.3. MN stimulation (10 Hz, 5 s) usually abolished contractions of the longitudinal and circular muscles evoked by either electrical or mechanical stimuli.4. The inhibition was mimicked by UK14,304 (70-100 nM) and abolished by idazoxan (100 nM), revealing an enhancement of circular muscle contractions. There was no evidence for a 2 -receptors on the muscle, suggesting sympathetic inhibition was via the myenteric plexus.5. Possible sites of action of noradrenaline released from sympathetic nerves were investigated using intracellular recordings from the circular muscle in a multichambered organ bath.6. When in the stimulation chamber, UK14,304 depressed (by 50 %) excitatory junction potentials (EJPs) recorded oral to a distension stimulus, but did not affect inhibitory junction potentials (IJPs) recorded anal to the stimulus. When added to a chamber between the stimulus and recording chambers, UK14,304 depressed EJPs by 40 %, but did not alter IJPs. When in the recording chamber, UK14,304 depressed EJPs by 20 %, but had no effect on IJPs. IJPs were inhibited, however, when UK14,304 was applied to the whole bath.7. It is concluded that sympathetic activity inhibits intestinal motility mainly via a 2 -adrenoceptors on ascending interneurons and intrinsic sensory neurons of the orally directed reflex pathway.

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Section: Excitatory Effects Of Mn Stimulationsupporting

confidence: 90%

Role of α₂‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum

Stebbing

Johnson

Vremec

et al. 2001

The Journal of Physiology

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“…Similarly Day & Rand (1961) carried out experiments on cat isolated atria in which they stimulated the sympathetic fibres at 50 shocks/sec. When guanethidine was added to the bath to block the release of noradrenaline, stimulation produced well-marked inhibitory effects.…”

Section: Discussionmentioning

confidence: 99%

The Release of Acetylcholine by Sympathetic Nerve Stimulation at Different Frequencies

Burn

Dromey

Large

1963

British Journal of Pharmacology and Chemotherapy

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Supramaximal stimulation of the periarterial nerves in the mesentery to the rabbit isolated ileum causes inhibition which is increased when hyoscine is added to the bath. This increase is, however, usually seen only when the stimulus frequency is low, and the addition of hyoscine usually makes no difference when the frequency is 10 shocks/sec or more. The observations suggest that, at low frequency, stimulation releases both acetylcholine and noradrenaline, but that at higher frequencies only noradrenaline is released. Similar observations have been made for the nictitating membrane of the cat. When the postganglionic fibres from the superior cervical ganglion were stimulated supramaximally, the contractions of the membrane increased in size as the frequency rose. In the presence of hyoscine the contractions were smaller, the greatest difference being for the lowest stimulus frequency, the difference diminishing as the frequency rose. These observations are consistent with the view that sympathetic choli-nergic fibres in many situations release acetylcholine to act directly only at low frequencies, and that at higher frequencies the acetylcholine is almost entirely used to release noradrenaline.When sympathetic postganglionic nerve fibres are stimulated, noradrenaline is released, and in addition acetylcholine may be released. In a recent paper (Burn & Weetman, 1963) experiments were described in which it appeared that acetylcholine was released together with noradrenaline when stimulation was applied at lower frequencies but that, at higher frequencies, only noradrenaline was released. These observations were made with the isolated vas deferens of the guinea-pig, stimulation being applied to the hypogastric nerve.While the hypogastric nerve seems to be largely composed of postganglionic fibres, preganglionic fibres are also present. Moreover Vogt (1963) has found chromaffin cells in the hypogastric nerve of the dog. Sj6strand (1962) observed that hexamethonium blocked the response to stimulation of the hypogastric nerve in the guinea-pig. In addition, Ohlin & Str6mblad (1963) reported that hexamethonium (3.7 x 10-M) blocked the response to stimulation of the hypogastric nerve when the electrodes were 3 to 5 cm from the organ, but not when the electrodes were 1 to 5 mm from the organ. Experiments have therefore been carried out with other organs where the fibres stimulated were all postganglionic. The rabbit isolated ileum was used, stimulation being applied to the periarterial nerves to inhibit the rhythmical contractions, and in addition the nictitating membrane of the cat anaesthetized with chloralose was used, stimulation being applied to the fibres leaving the superior

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“…The results of investigations in this field are often contradictory and many issues remain the subject of controversy (Chang & Rand, 1960;Day & Rand, 1961;Gillespie & MacKenna, 1961;Bentley, 1962).…”

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confidence: 99%

Effect of Some Blocking Drugs on the Pressor Response to Physostigmine in the Rat

Gokhale

Gulati

Joshi

1963

British Journal of Pharmacology and Chemotherapy

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Bretylium and guanethidine blocked the pressor effect of physostigmine and potentiated the responses to adrenaline and noradrenaline on the blood pressure of the rat. Morphine and atropine in small doses blocked the pressor effect of physostigmine without interfering with the actions of adrenaline and noradrenaline. Chlorpromazine in small doses (0.5 to 2.5 mg/kg) blocked the pressor effect of physostigmine and potentiated the responses to noradrenaline whilst those to adrenaline remained unaltered. 3,6-Di(3-diethylaminopropoxy)pyridazine di(methiodide) (Win 4981) blocked the pressor effect of physostigmine and, in its early stages, this block was partially reversed by choline chloride. N-Diethylaminoethyl-N-isopentyl-N'N'-diisopropylurea (P-286), in a dose that reduced the effect of dimethylphenylpiperazinium, had no effect on the pressor response to physostigmine or on the responses to adrenaline and noradrenaline. Hexamethonium, even in large doses (100 mg/kg), only blocked partially the effect of physostigmine while mecamylamine produced a complete block; the responses to adrenaline and noradrenaline were potentiated in both instances.

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Effect of Guanethidine in Revealing Cholinergic Sympathetic Fibres

Cited by 46 publications

References 33 publications

Role of α₂‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum

Role of α₂‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum

The Release of Acetylcholine by Sympathetic Nerve Stimulation at Different Frequencies

Effect of Some Blocking Drugs on the Pressor Response to Physostigmine in the Rat

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Effect of Guanethidine in Revealing Cholinergic Sympathetic Fibres

Cited by 46 publications

References 33 publications

Role of α2‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum

Role of α2‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum

The Release of Acetylcholine by Sympathetic Nerve Stimulation at Different Frequencies

Effect of Some Blocking Drugs on the Pressor Response to Physostigmine in the Rat

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Role of α₂‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum

Role of α₂‐adrenoceptors in the sympathetic inhibition of motility reflexes of guinea‐pig ileum