Effects of clonidine and l-dopa on spontaneous and evoked splanchnic nerve discharges

Sinha, J. N.; Atkinson, Judith M.; Schmitt, H

doi:10.1016/0014-2999(73)90122-2

Cited by 56 publications

(8 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Intracisternal administrations were chosen in this work as the medulla oblongata appeared to be the main site of action of clonidine (Sinha, Atkinson & Schmitt, 1973). By this route it would be expected that the effect of pharmacological agents would be exerted mainly on the medulla oblongata, although diffusion into the ventral surface of the brain and the upper spinal cord has been shown (Tsoucaris-Kupfer & Schmitt, 1972).…”

Section: Discussionmentioning

confidence: 99%

Blockade of the Central Hypotensive Effect of Clonidine by ?-Adrenoreceptor Antagonists in Rats, Rabbits and Dogs

Bogaievsky

Tsoucaris-Kupfer

et al. 1974

Clin Exp Pharmacol Physiol

View full text Add to dashboard Cite

1. Clonidine and three a-adrenoreceptor blocking agents were injected into the cisterna magna of rats, rabbits and dogs. Clonidine (1 pg.kg-') induced a fall in blood pressure in the three species.2. Phentolamine, tolazoline and phenoxybenzamine (100 ,ug.kg-l) induced a fall in blood pressure in rats, but only phentolamine was effective in rabbits, and none of these drugs significantly altered blood pressure in dogs when given intracisternally.3. A subsequent administration of clonidine after recovery of blood pressure no longer decreased blood pressure in rats and rabbits.4. In dogs the effects of clonidine were antagonized by tolazoline and phentolamine, but not by phenoxybenzamine.5. These results indicate that clonidine stimulates central a-adrenoreceptors to produce a decrease in blood pressure, but the structure of these receptors may vary according to animal species.

show abstract

Section: Discussionmentioning

confidence: 99%

Blockade of the Central Hypotensive Effect of Clonidine by ?-Adrenoreceptor Antagonists in Rats, Rabbits and Dogs

Bogaievsky

Tsoucaris-Kupfer

et al. 1974

Clin Exp Pharmacol Physiol

View full text Add to dashboard Cite

show abstract

“…inhibit the activity of these neurones. Moreover, it has been suggested that an action of clonidine at spinal sites mediates the observed sympathoinhibitory effects of this drug when administered by several central or peripheral routes (Sinha, Atkinson & Schmitt, 1973;Smith, 1974;Dhawan, Johri, Singh, Srimal & Viswesaram, 1975 The second phase of the CCh response was unco-ordinated in the sense that shivering was present at the same time as tail skin vasodilatation. It is possible that…”

Section: Discussionmentioning

confidence: 99%

The thermoregulatory effects of noradrenaline, serotonin and carbachol injected into the rat spinal subarachnoid space

LoPachin

Rudy

1982

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. We have examined the effects on thermoregulation in the rat of noradrenaline bitartrate (NA), 5-hydroxytryptamine hydrochloride (5-HT) and carbamylcholine chloride (CCh) injected into the lumbar spinal subarachnoid space via a chronic indwelling catheter.2. Intrathecal injections of the monoamines and CCh reproducibly affected thermoregulation, whereas injections of control solutions had no effect.3. Intrathecal injections of NA (001-030 smol) produced a dose-dependent hypothermia associated with a decrease in tail skin vasomotor tone. Shivering activity was not depressed during the hypothermia and sometimes increased.Intrathecal administration of the a-adrenergic agonist clonidine (00175-0070 Itmol) elicited changes in Tc and Tsk similar to those induced by intrathecal NA.4. Intrathecal 5-HT (0030-090 ,mol) elicited a dose-dependent hyperthermia accompanied by increased tail skin vasomotor tone and increased shivering.5. CCh injected intrathecally (0001-0406 #smol) evoked a dose-dependent hyperthermia. During the period when core temperature was rising, tail skin vasomotor tone increased and shivering-like activity was present. Once the maximum core temperature had been reached, tail skin vasodilatation occurred. Vasodilatation persisted until core temperature had returned to normal.6. Intravenous injections of 5-HT (030 and 090 /smol) or CCh (0006 and 003 tmol) caused no thermoregulatory effect. The effects of these agents injected intrathecally were therefore not due to an action in the periphery.7. Intravenous infusions of NA (006 and 0 10 smol) produced hypothermia and transient tail skin vasodilatation. We suggest that an action at peripheral sites may have contributed to the effects produced by intrathecal injection of this monamine.8. These findings suggest that spinal noradrenergic, serotonergic and cholinergic synapses may be importantly involved in the control of body temperature in the rat. The possible functional roles of these synapses and the putative spinal sites of action of the injected substances are discussed. R. M. LOPACHIN AND T. A RUDY

show abstract

“…The authors accounted for this result by postulating a medullary site of action for both effects. Clonidine in cats and dogs reduced the hypertension induced by central sciatic nerve stimulation but at rather high doses (30 flog/kg); the effect was more marked when the frequency of stimulation was low (SINHA et al, 1973).…”

Section: J Effects Of Clonidine On Cardiovascular Reflexesmentioning

confidence: 99%

The Pharmacology of Clonidine and Related Products

Schmitt¹

1977

Antihypertensive Agents

Self Cite

125

View full text Add to dashboard Cite

Effects of clonidine and l-dopa on spontaneous and evoked splanchnic nerve discharges

Cited by 56 publications

References 22 publications

Blockade of the Central Hypotensive Effect of Clonidine by ?-Adrenoreceptor Antagonists in Rats, Rabbits and Dogs

Blockade of the Central Hypotensive Effect of Clonidine by ?-Adrenoreceptor Antagonists in Rats, Rabbits and Dogs

The thermoregulatory effects of noradrenaline, serotonin and carbachol injected into the rat spinal subarachnoid space

The Pharmacology of Clonidine and Related Products

Contact Info

Product

Resources

About