, Volume 99, Issue 3, pp 304–308 | Cite as

The effects of intrathecal administration of the dopamine agonist apomorphine on penile reflexes and copulation in the male rat

  • Elizabeth A. Pehek
  • James T. Thompson
  • Elaine M. Hull
Original Investigations


Relatively high doses of systemically administered apomorphine inhibit penile reflexes. It is possible that these inhibitory effects are due, at least in part, to actions of apomorphine on the lumbosacral spinal cord. The present experiments examined this possibility by injecting apomorphine (10 and 50 μg/5.0 μl vehicle) into the lumbosacral subarachnoid space through chronic, indwelling cannulae. Such injections impaired ex copula penile reflexes, slowed the rate of copulation, and decreased the number of intromissions preceding ejaculation. These results suggest that lumbosacral cord dopamine receptors may normally regulate male sexual performance.

Key words

Apomorphine Dopamine Penile reflex Sexual behavior Spinal cord Rat 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Ahlenius S, Larsson K (1984) Apomorphine and haloperidol-induced effects on male rat sexual behavior: no evidence for actions due to stimulation of central dopamine autoreceptors. Pharmacol Biochem Behav 21:463–466Google Scholar
  2. Arnold AP, Gorski RA (1984) Gonadal steroid induction of structural sex differences in the central nervous system. Annu Rev Neurosci 7:413–442Google Scholar
  3. Beach FA (1956) Characteristics of masculine “sex drive”. In: Jones MR (ed) The Nebraska symposium on motivation. University of Nebraska Press, Lincoln, Nebraska, pp 1–32Google Scholar
  4. Benassi-Benelli A, Ferrari F, Pellegrini Quarantotti B (1979) Penile erection induced by apomorphine and N-n-propyl-norapomorphine in rats. Arch Int Pharmacodyn 242:241–247Google Scholar
  5. Clark JT, Smith ER (1987) Effects of apomorphine on sexual behavior in young and middle-aged rats. Neurobiol Aging 8:153–157Google Scholar
  6. Falaschi P, Rocco A, De Giorgio G, Frajese G, Fratta W, Gessa GL (1981) Brain dopamine and premature ejaculation: results of treatment with dopamine antagonists. In: Gessa GL, Corsini GU (eds) Apomorphine and other dopaminomimetics, vol 1, Basic Pharmacology. Raven Press, New York, pp 117–121Google Scholar
  7. Gower AJ, Berendson HHG, Princen MM, Broekkamp CLE (1984) The yawning-penile erection syndrome as a model for putative dopamine autoreceptor activity. Eur J Pharmacol 103:81–89Google Scholar
  8. Hansen S (1982) Spinal control of sexual behavior: effects of intrathecal administration of lisuride. Neurosci Lett 33:329–332Google Scholar
  9. Hart BL (1968) Sexual reflexes and mating behavior in the male rat. J Comp Physiol Psychol 65:453–460Google Scholar
  10. Hull EM, Bitran D, Pehek EA, Warner RK, Band LC, Holmes GM (1986) Dopaminergic control of male sex behavior in rats: effects of an intracerebrally-infused agonist. Brain Res 370:73–81Google Scholar
  11. Hull EM, Warner RK, Bazzett TJ, Eaton RC, Thompson JT, Scaletta LL (1989) D2/D1 ratio in the medial preoptic area affects copulation of male rats. J Pharm Exp Ther (in press)Google Scholar
  12. LoPachin RM, Rudy TA (1981) An improved method for chronic catheterization of the rat spinal subarachnoid space. Physiol Behav 27:559–561Google Scholar
  13. Nadelhaft I, Booth AM (1984) The location and morphology of preganglionic neurons and the distribution of visceral afferents from the rat pelvic nerve: an HRP study. J Comp Neurol 226:238–245Google Scholar
  14. Napoli-Farris L, Fratta W, Gessa GL (1984) Stimulation of dopamine autoreceptors elicits “premature ejaculation” in rats. Pharmacol Biochem Behav 20:69–72Google Scholar
  15. Paglietti E, Pellegrini Quarantotti B, Mereu G, Gessa GL (1978) Apomorphine and l-DOPA lower ejaculation threshold in the male rat. Physiol Behav 20:559–562Google Scholar
  16. Pehek EA, Thompson JT, Eaton RC, Bazzett TJ, Hull EM (1988) Apomorphine and haloperidol, but not domperidone, affect penile reflexes in rats. Pharmacol Biochem Behav 31:201–208Google Scholar
  17. Pehek EA, Thompson JT, Hull EM (1989) The effects of intracranial administration of the dopamine agonist apomorphine on penile reflexes and seminal emission in the rat. Brain Res (in press)Google Scholar
  18. Sachs BD (1978) Conceptual and neural mechanisms of masculine copulatory behavior. In: McGill TE, Dewsbury DA, Sachs BD (eds) Sex and behavior: status and prospectus. Plenum Press, New York, pp 267–296Google Scholar
  19. Sachs BD (1983) Potency and fertility: hormonal and mechanical causes and effects of penile actions in rats. In: Balthazart J, Pröve E, Gilles R (eds) Hormones and behavior in higher vertebrates. Springer, Berlin Heidelberg New York, pp 86–110Google Scholar
  20. Serra G, Collu M, Loddo A, Celasco G, Gessa GL (1983) Hypophysectomy prevents yawning and penile erection but not hypomotility induced by apomorphine. Pharmacol Biochem Behav 19:917–919Google Scholar
  21. Skagerberg G, Lindvall O (1985) Organization of diencephalic dopamine neurons projecting to the spinal cord in the rat. Brain Res 342:340–351Google Scholar
  22. Skagerberg G, Björklund A, Lindvall O, Schmidt RH (1982) Origin and termination of the diencephalo-spinal dopamine system in the rat. Brain Res Bull 9:237–244Google Scholar
  23. Stefanick ML, Smith ER, Clark JT, Davidson JM (1982) Effects of a potent dopamine receptor agonist, RDS-127, on penile reflexes and seminal emission in intact and spinally transected rats. Physiol Behav 29:973–978Google Scholar
  24. Svensson L, Hansen S (1984) Spinal monoaminergic modulation of masculine copulatory behavior in the rat. Brain Res 302:315–321Google Scholar
  25. Tagliamonte A, Fratta W, del Fiacco M, Gessa GL (1974) Possible stimulatory role of brain dopamine in the copulatory behavior of male rats. Pharmacol Biochem Behav 2:257–260Google Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Elizabeth A. Pehek
    • 1
  • James T. Thompson
    • 1
  • Elaine M. Hull
    • 1
  1. 1.Department of PsychologyState University of New York at BuffaloBuffaloUSA

Personalised recommendations