Effect of cholinergic stimulation of the medial septal area on the secretory properties of atrial myocardial fibers.
Adult male Wistar rats weighing 240-260 g were implanted with stainless steel guide cannulae into the medial septal area (MSA). Cholinergic stimulation of the MSA increased natriuresis (344.6 +/- 13.8 vs 22.2 +/- 2.1 microEq for the controls), the number of atrial specific granules (61.0 +/- 6.7 vs 43.8 +/- 3.5 granules/100 microns 2 sarcoplasma for the controls), and the number of electron-dense vesicles near the sarcolemma or appearing to undergo exocytotic extrusion (50.0 +/- 2.3 vs 21.4 +/- 5.7 vesicles/100 microns sarcolemma for the controls). It is not yet clear how cholinergic stimulation of the MSA changes the secretory characteristics of atrial myocardial fibers. However, the present study provides evidence that release of an atrial natriuretic factor may be controlled by the central nervous system (CNS). This may occur through the sympathetic and parasympathetic innervation of the heart or through the release of some substance produced by the CNS or produced at another site whose release is controlled by the CNS.
Rocha
M J
MJ
Departamento de Fisiologia, Universidade de São Paulo, Ribeirão Preto, Brasil.
Moreira
J E
JE
Kohler
F W
FW
Gonçalves
R P
RP
Franci
C R
CR
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure*; D010277:Parasympathomimetics / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012686:Septal Nuclei / Q000502:physiology*; D012964:Sodium / Q000652:urine
D010277:Parasympathomimetics; D009320:Atrial Natriuretic Factor; D012964:Sodium