Dopamine inhibits ATP-induced responses in the cat petrosal ganglion in vitro.
The petrosal ganglion (PG) provides sensory innervation to the carotid sinus and carotid body through the carotid (sinus) nerve (CN). Application of either acetylcholine (ACh) or adenosine 5'-triphosphate (ATP) to the PG superfused in vitro activates CN fibers. Dopamine (DA) modulates the effects of ACh. We have previously shown that DA when applied to the PG modulates the effects of ACh on carotid sinus nerve fibers. We currently report the effects of DA on the ATP-induced responses in the isolated PG in vitro. While DA had no effect on the basal activity recorded from the CN, it reduced ATP-induced responses in a dose-dependent manner, when preceding ATP applications by 30 s. Our results suggest that DA-a transmitter present in a group of PG neurons and in carotid body cells-may act as an inhibitory modulator of ATP-evoked responses in PG neurons.
Alcayaga
Julio
J
Laboratorio de Fisiología Celular, Departamento de Biologi;a, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile. jalcayag@uchile.cl
Retamal
Mauricio
M
Cerpa
Verónica
V
Arroyo
Jorge
J
Zapata
Patricio
P
D000109:Acetylcholine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D002415:Cats; D004298:Dopamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D017950:Ganglia, Sensory / Q000187:drug effects* / Q000502:physiology; D005930:Glossopharyngeal Nerve / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009434:Neural Pathways / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D010477:Perfusion
D000255:Adenosine Triphosphate; D000109:Acetylcholine; D004298:Dopamine