title: Pharmacological control of the pattern of activity in leech Retzius neurones.
abstract: 1. Changes in the activity pattern of leech Retzius (R) cells were investigated using intracellular recording. 2. The presence of an after-hyperpolarisation (AHP) is closely related to activity pattern; regular firing being associated with an AHP, bursting with its absence. 3. Increasing external calcium (Cao), cyclic AMP levels or activity of kinase A enhanced the AHP. 4. Bursting was induced by low Cao, EGTA, barium, cobalt or injection of phorbol ester. 5. Reduction of Cao to zero caused long paroxysmal depolarising shifts of potential which could be reversed to bursting by cobalt, IBMX or injection of kinase A catalytic subunit. 6. The possible roles of a calcium-activated potassium channel and protein phosphorylation in regulating the activity of the cell are discussed.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D007477:Ions; D007865:Leeches / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism
chemical_list: D007477:Ions; D011506:Proteins; D003994:Bucladesine; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine