Role of serotonin receptor subtypes in the development of amygdaloid kindling in rats

The present study was conducted to identify serotonin (5-HT) receptor subtypes involved in the development of amygdala (AM) kindling. We used 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A agonist, and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a 5-HT2 agonist, both of which were injected subcutaneously 15 min prior to each daily electrical stimulation to the rat AM. Treatment with 8-OH-DPAT (1 mg/kg) slightly suppressed behavioral and electrographic seizure development during the course of kindling. In contrast, DOI (1 mg/kg) strongly facilitated kindling development and reduced the number of stimulations needed to produce generalized seizures. These facilitatory effects of DOI were completely blocked by pretreatment with a 5-HT2 antagonist ketanserin. The present results suggest that the activation of 5-HT1A receptors can retard the development of AM kindling, whereas 5-HT2 receptors play a facilitatory role in this developmental seizure process.

[1]  C. de Montigny,et al.  Modification of 5‐HT neuron properties by sustained administration of the 5‐HT1A agonist gepirone: Electrophysiological studies in the rat brain , 1987, Synapse.

[2]  R. Glennon,et al.  Withdrawal from chronic treatment with (+/-)-DOI causes super-sensitivity to 5-HT2 receptor-induced head-twitch behaviour in mice. , 1990, European journal of pharmacology.

[3]  C. Sotelo,et al.  Direct Immunohistochemical Evidence of the Existence of 5‐HT1A Autoreceptors on Serotoninergic Neurons in the Midbrain Raphe Nuclei , 1990, The European journal of neuroscience.

[4]  R. Nicoll,et al.  Pharmacologically distinct actions of serotonin on single pyramidal neurones of the rat hippocampus recorded in vitro. , 1987, The Journal of physiology.

[5]  D. Middlemiss,et al.  Centrally active 5-HT receptor agonists and antagonists , 1992, Neuroscience & Biobehavioral Reviews.

[6]  J. Palacios,et al.  Quantitative autoradiographic mapping of serotonin receptors in the rat brain. I. Serotonin-1 receptors , 1985, Brain Research.

[7]  J W Dailey,et al.  Evidence that a serotonergic mechanism is involved in the anticonvulsant effect of fluoxetine in genetically epilepsy-prone rats. , 1994, European journal of pharmacology.

[8]  Y. Wada,et al.  Suppressive effects ofl-5-hydroxytryptophan in a feline model of photosensitive epilepsy , 1991, Brain Research.

[9]  D. Mckenna.  Chronic treatment with (W)DOI, a psychotomimetic 5-HT2 agonist, downregulates 5-HT2 receptors in rat brain , 1989 .

[10]  R. North,et al.  5‐Hydroxytryptamine acts at 5‐HT2 receptors to decrease potassium conductance in rat nucleus accumbens neurones. , 1989, The Journal of physiology.

[11]  J. Fozard,et al.  The involvement of subtypes of the 5-HT1 receptor and of catecholaminergic systems in the behavioural response to 8-hydroxy-2-(di-n-propylamino)tetralin in the rat. , 1984, European journal of pharmacology.

[12]  DH Bobker.  A slow excitatory postsynaptic potential mediated by 5-HT2 receptors in nucleus prepositus hypoglossi , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[13]  R. Andrade,et al.  5-Hydroxytryptamine2 and 5-hydroxytryptamine1A receptors mediate opposing responses on membrane excitability in rat association cortex , 1991, Neuroscience.

[14]  R. Racine,et al.  Kindling: basic mechanisms and clinical validity. , 1990, Electroencephalography and clinical neurophysiology.

[15]  Y. Wada,et al.  Behavioral and electroencephalographic effects of a serotonin receptor agonist (5-methoxy-N,N-dimethyltryptamine) in a feline model of photosensitive epilepsy , 1992, Neuroscience Letters.

[16]  K. Alkadhi,et al.  Inhibition of epileptiform activity by serotonin in rat CA1 neurons , 1995, Brain Research.

[17]  Nariyoshi Yamaguchi,et al.  Role of serotonin receptor subtype in seizures kindled from the feline hippocampus , 1992, Neuroscience Letters.

[18]  Nariyoshi Yamaguchi,et al.  Intra-hippocampal injection of 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) inhibits partial and generalized seizures induced by kindling stimulation in cats , 1993, Neuroscience Letters.

[19]  D. Taylor,et al.  Involvement of 5-HT2 receptors in the wet-dog shake behaviour induced by 5-hydroxytryptophan in the rat , 1983, Neuropharmacology.

[20]  R. Racine,et al.  Modification of seizure activity by electrical stimulation. II. Motor seizure. , 1972, Electroencephalography and clinical neurophysiology.

[21]  M. Pranzatelli.  Evidence for involvement of 5-HT2 and 5-HT1C receptors in the behavioral effects of the 5-HT agonist 1-(2,5-dimethoxy-4-iodophenyl aminopropane)-2 (DOI) , 1990, Neuroscience Letters.

[22]  A. Colino,et al.  Differential modulation of three separate K-conductances in hippocampal CA1 neurons by serotonin , 1987, Nature.

[23]  M. E. Corcoran,et al.  Frontal Lobe and Kindling in the Rat , 1975, Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques.

[24]  R. Glennon,et al.  Behavioral evidence for differential adaptation of the serotonergic system after acute and chronic treatment with (+/- )-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) or ketanserin. , 1992, The Journal of pharmacology and experimental therapeutics.