title: Pulses of cholinergic receptor escape from atropine blocking reflect major natural periodicities.
abstract: 1. Semi-lunar variation in cardiac response to applied acetylcholine was reconfirmed. 2. Atropine completely blocked the effects of acetylcholine on the heart except for brief pulses of escape at 12-hr intervals which began at moonset and progressed through midday at 10 to 14-day intervals. 3. The direction of escape, i.e. inhibition or acceleration, reversed at the winter solstice and at both equinoxes. 4. Cholinergic receptors in the cardiac preparation seem to reflect the following: 12-hr intervals beginning at moonset, 24.8 hr. 10 to 14-day intervals, 14.8-day intervals and the equinoxes and solstices. 90-day intervals.
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D002940:Circadian Rhythm; D006321:Heart / Q000187:drug effects*; D010507:Periodicity; D010526:Periplaneta; D011950:Receptors, Cholinergic / Q000502:physiology*; D012621:Seasons
chemical_list: D011950:Receptors, Cholinergic; D001285:Atropine; D000109:Acetylcholine