, Volume 86, Issue 1, pp 31–36

Cocaine: Excitatory effects on sensorimotor reactivity measured with acoustic startle

  • Michael Davis
Original Investigations

DOI: 10.1007/BF00431680

Cite this article as:
Davis, M. Psychopharmacology (1985) 86: 31. doi:10.1007/BF00431680


Cocaine (2.5–10 mg/kg) caused a dose-related increase in the amplitude of the acoustic startle reflex in rats. In contrast, procaine (5–40 mg/kg) caused a dose-related decrease in startle, indicating that the effects of cocaine could not be ascribed to its local anesthetic effects. Cocaine's excitatory effects were blocked by pretreatment with haloperidol (0.5 mg/kg) but not by cyproheptadine or prazosin. The excitatory effects of cocaine (10 mg/kg) were markedly attenuated by pretreatment with reserpine (5 mg/kg 24 and 18 h earlier) but not by α-methyl-p-tyrosine (100 mg/kg 1 h earlier). In contrast, comparably sized excitatory effects of d-amphetamine were blocked by α-methyl-p-tyrosine and greatly enhanced by pretreatment with reserpine. Neither pretreatment blocked excitatory effects of apomorphine on startle. The data indicate that cocaine increases startle by acting through reserpine-sensitive pools of dopamine and provide further support for the conclusion that acoustic startle is enhanced by activation of dopamine receptors.

Key words

Cocaine Startle Acoustic startle Amphetamine Apomorphine Stimulants 

Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • Michael Davis
    • 1
    • 2
  1. 1.Yale University School of MedicineNew HavenUSA
  2. 2.The Ribicoff Research Facilities of the Connecticut Mental Health CenterNew HavenUSA

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