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Effect of post-trial injection of beta adrenergic blocking agents on a conditioned reflex in rats

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The effect of beta adrenergic blocking agents (propranolol, pronethalol, INPEA and dichloroisoproterenol) on the acquisition of a conditioned reflex was studied in adult, male Wistar rats. The experiments were done in a shuttle box with light as a conditioned stimulus, and an electric shock to the legs through the grid as the unconditioned stimulus. A maximum of 23 sessions were carried out with 24 h intervals. The drugs, the peripheral effects of which are estimated to last less than 24 h, were injected i.p. post-trial.

The learning process and the number of animals which succeeded in complying with the learning criterion until session 23 were improved by propranolol (2 mg/kg) and pronethalol (10 mg/kg). INPEA (10 mg/kg) only increased the percentage of animals which succeeded in complying the learning criterion until session 12. In the initial sessions dichloroisoproterenol (10 mg/kg) impaired the learning process.

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Fellow of the Consejo Nacional de Investigaciones Cientificas y Técnicas, Argentina.

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Merlo, A.B., Izquierdo, J.A. Effect of post-trial injection of beta adrenergic blocking agents on a conditioned reflex in rats. Psychopharmacologia 22, 181–186 (1971). https://doi.org/10.1007/BF00403626

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  • Chronic Conditioned Reflex
  • Rats
  • Beta Adrenergic Blocking Agents