Skip to main content
SpringerLink
Log in

Effects of phentolamine, dihydroergocristine and isoxsuprine on the blood pressure and heart rate in normotensive, hypotensive and hypertensive rats

  • Published:
Naunyn-Schmiedeberg's Archives of Pharmacology Aims and scope Submit manuscript

Summary

Phentolamine, dihydroergocristine and isoxsuprine were compared for their effects on the blood pressure in anaesthetized normotensive rats, in rats made hypotensive by ganglionic blockade or by pithing and in rats with noradrenaline-induced hypertension. Their ability to inhibit pressor responses elicited by electrical stimulation of the posterior hypothalamus and of the sympathetic outflow from the spinal cord was also investigated.

All three drugs appeared very potent in inhibiting noradrenaline-induced hypertension and caused a dose-dependent fall in blood pressure in normotensive rats, which however was less pronounced with dihydroergocristine than with phentolamine and isoxsuprine. In hypotensive rats, dihydroergocristine caused a rise in blood pressure.

At higher doses than those required to block noradrenaline-induced hypertension, the three drugs inhibited pressor responses elicited by electrical stimulation and were equally active on peripherally- and centrally-evoked responses.

Simultaneous recording of heart rate and blood pressure, both in anaesthetized and in pithed rats, indicated a reflex origin for phentolamine-induced tachycardia and a direct cardiac stimulation for isoxsuprine. Reflex changes of heart rate were not observed with dihydroergocristine.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Ariëns, E. J., Waelen, M. J. G. A., Sonneville, P. F., Simonis, A. M.: The pharmacology of catecholamines and their derivatives. Arzneimittel.-Forsch. 13, 541–546 (1963)

    Google Scholar 

  • Berde, B.: Some new vascular and biochemical aspects of the mechanism of action of ergot compounds. Headache 11, 139–147 (1972)

    Google Scholar 

  • Bircher, R., Cerletti, A.: Pharmakodynamische Grundlagen der Therapie von Kreislaufstörungen mit den Dihydroalkaloiden des Mutterkorns. Helv. med. Acta 26, 13–26 (1949)

    Google Scholar 

  • Brücke, F., Hertting, G., Linder, A., Loudon, M.: Zur Pharmakologie einer neuen gefäßerweiternden Substanz aus der p-Oxy-Ephedrin-Reihe. Wien. klin. Wschr. 68, 183–186 (1956)

    Google Scholar 

  • Das, P. K., Parratt, J. R.: Myocardial and haemodynamic effects of phentolamine. Brit. J. Pharmacol. 41, 437–444 (1971)

    Google Scholar 

  • Gillespie, J. S., Muir, T. C.: A method of stimulating the complete sympathetic outflow from the spinal cord to blood vessels in the pithed rat. Brit. J. Pharmacol. 30, 78–87 (1967)

    Google Scholar 

  • Goodman, L., Gilman, A. in: Pharmacological basis of therapeutics, p. 558. New York: Mac Millan Co. 1970

    Google Scholar 

  • Hilliard, C. C., Bagwell, E. E., Daniell, H. B.: Effects of sympathetic and central nervous system alterations on the blood pressure responses to phentolamine. J. Pharmacol. exp. Ther. 180, 743–747 (1972)

    Google Scholar 

  • Konzett, H., Rothlin, E.: Investigations on the hypotensive effect of the hydrogenated ergot alkaloids. Brit. J. Pharmacol. 8, 201–207 (1953)

    Google Scholar 

  • Lish, P. M., Dungan, K. W., Peters, E. L.: A survey of the effects of isoxsuprine on nonvascular smooth muscle. J. Pharmacol. exp. Ther. 129, 191–199 (1960)

    Google Scholar 

  • Manley, E. S., Lawson, J. W.: Effect of beta adrenergic receptor blockade on skeletal muscle vasodilatation produced by isoxsuprine and nylidrin. Arch. int. Pharmacodyn. 175, 239–250 (1968)

    Google Scholar 

  • Morpurgo, C.: Pharmacological modifications of sympathetic responses elicited by hypothalamic stimulation in the rat. Brit. J. Pharmacol. 34, 532–542 (1968)

    Google Scholar 

  • Nickerson, M., Hollenberg N. K.: Adrenergic blocking drugs, in: Physiological pharmacology, Vol. 4, part D, eds. W. S. Root and F. C. Hoffman p. 243. New York: Academic Press Inc., 1967

    Google Scholar 

  • Pettinger, W., Sheppard, H., Palkoski, Z., Renyi, E.: Angiotensin antagonism and antihypertensive activity of phosphodiesterase inhibiting agents. Life Sci. 12 (I), 49–62 (1973)

    Google Scholar 

  • Rothlin, E.: The pharmacology of the natural and dihydrogenated alkaloids of ergot. Bull. Acad. Swiss. Sci. Med. 2, 249–273 (1947)

    Google Scholar 

  • Shipley, R. E., Tilden, J. H.: A pithed rat preparation suitable for assaying pressor substances. Proc. Soc. exp. Biol. (N.Y.) 64, 453–455 (1947)

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. POLI Research Department, Milano

    Clara Morpurgo, Daniela Faini & A. Falcone

Authors
  1. Clara Morpurgo
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Daniela Faini
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. A. Falcone
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Morpurgo, C., Faini, D. & Falcone, A. Effects of phentolamine, dihydroergocristine and isoxsuprine on the blood pressure and heart rate in normotensive, hypotensive and hypertensive rats. Naunyn-Schmiedeberg's Arch. Pharmacol. 290, 335–346 (1975). https://doi.org/10.1007/BF00499947

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00499947

Key words

Search

Navigation