Effects of sulphated cholecystokinin octapeptide (CCK-8) on the dorsal motor nucleus of the vagus.
Sulphated cholecystokinin octapeptide (CCK-8) was applied by superfusion (2.1 x 10(-7) to 4.2 x 10(-6) M) to neurons of the dorsal motor nucleus of the vagus (DMV) in slice preparations of the rat medulla oblongata. Intracellular recordings show 23 of 54 (43%) neurons to be depolarized and the depolarization to be associated with an increase in membrane input resistance; 6 of 54 (11%) neurons were hyperpolarized and the hyperpolarization was associated with a decrease in membrane input resistance. Both effects were dose-dependent, reversible and persisted after blockade of synaptic transmission by Ca2+ free/high Mg2+ solution. On the other hand, nonsulphated CCK-8, a nonactive analogue of CCK-8, had no effect. These data show that vagal neurons in the DMV have receptors for CCK-8 and that CCK-8 may modulate vagal output mainly by increasing neuronal excitability.
Plata-Salamán
C R
CR
Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Fukuda
A
A
Oomura
Y
Y
Minami
T
T
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012844:Sincalide / Q000494:pharmacology; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology*
D012844:Sincalide