Acetylcholine-sensitive cells in the caudal medulla of the rat: distribution, pharmacology and effects of pentobarbitone.
1. The distribution of cholinoceptive and non-cholinoceptive cells in various nuclei of the caudal medulla of the rat is described. 2. The nature of the responses of cells of the paramedian reticular nucleus and of the perihypoglossal nuclei to electrophoretically applied acetylcholine (ACh) was investigated. 3. In unanaesthetized decerebrate preparations ACh responses were usually of a "fast onset-fast offset" nature. Dihydro-beta-erythroidine was a more effective antagonist than atropine. 4. In rats anaesthetized with barbiturate nearly all the tach responses showed a slower onset and prolonged action. Atropine was the more effective antagonist. 5. The synaptic responses of cells of the paramedian reticular and perihypoglossal nuclei to stimulation of glossopharyngeal, superior laryngeal, lingual and hypoglossal nerves were investigated. It is concluded that ACh does not mediate the responses at the level of these nuclei.
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D003655:Decerebrate State; D018691:Excitatory Amino Acid Antagonists; D005930:Glossopharyngeal Nerve / Q000187:drug effects; D007823:Laryngeal Nerves / Q000187:drug effects; D008036:Lingual Nerve / Q000187:drug effects; D008526:Medulla Oblongata / Q000187:drug effects*; D009292:Narcotic Antagonists / Q000494:pharmacology; D009431:Neural Conduction / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D010424:Pentobarbital / Q000494:pharmacology*; D051381:Rats; D011950:Receptors, Cholinergic; D013238:Stereotaxic Techniques; D009435:Synaptic Transmission / Q000187:drug effects
D018691:Excitatory Amino Acid Antagonists; D009292:Narcotic Antagonists; D011950:Receptors, Cholinergic; D001285:Atropine; D010424:Pentobarbital; D000109:Acetylcholine