Myoclonic and tonic seizures elicited by microinjection of cholinergic drugs into the inferior colliculus.
The inferior colliculus (IC) is the initiation site in the neuronal network for the epileptic audiogenic seizure (AGS). The present study investigates the effects of alteration of IC cholinergic transmission on the elicitation of epileptic seizures. Unilateral microinjections of carbachol (3 and 6 micrograms/0.2 microliter) into the IC elicited intense locomotor activity, contraversive rotations and myoclonic seizures. This result indicates that the IC is the initiation site for the induction of myoclonic seizures and suggests that these myoclonic seizures may result from activation of m1 muscarinic receptors. Microinjections of the nicotinic-muscarinic antagonist, gallamine (2 and 6 micrograms/0.2 microliter), into the IC induced AGS susceptibility. However, microinjections of muscarinic antagonists, atropine (15 micrograms/0.2 microliter) and scopolamine (12 and 20 micrograms/0.2 microliter), or the nicotinic antagonist, hexamethonium (12 and 20 micrograms/0.2 microliter), into the IC have no effect. Gallamine-induced AGS susceptibility may result from a selective blockade of m2 muscarinic receptors.
Bagri
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A
Département de Biologie Appliquée, Faculté des Sciences et Techniques, Université Hassan I, Settat, Morocco.
Di Scala
G
G
Sandner
G
G
D000109:Acetylcholine / Q000502:physiology*; D000161:Acoustic Stimulation / Q000009:adverse effects; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000633:toxicity*; D018678:Cholinergic Agents / Q000633:toxicity*; D004831:Epilepsies, Myoclonic / Q000139:chemically induced*; D020195:Epilepsy, Reflex / Q000139:chemically induced* / Q000503:physiopathology; D005703:Gallamine Triethiodide / Q000494:pharmacology / Q000633:toxicity*; D018738:Hexamethonium / Q000494:pharmacology; D007245:Inferior Colliculi / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects; D018727:Muscarinic Antagonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000502:physiology; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000502:physiology; D017661:Receptors, Presynaptic / Q000187:drug effects* / Q000502:physiology; D012601:Scopolamine / Q000494:pharmacology; D012640:Seizures / Q000139:chemically induced*
D018678:Cholinergic Agents; D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D017661:Receptors, Presynaptic; D018738:Hexamethonium; D001285:Atropine; D002217:Carbachol; D012601:Scopolamine; D000109:Acetylcholine; D005703:Gallamine Triethiodide