The involvement of catecholaminergic mechanisms in the appearance of wet dog shakes produced by carbachol chloride in rats.

Noradrenaline (NA), methoxamine, dopamine (DA), given intracerebroventricularly (ICV), and L-DOPA, administered systemically, significantly blocked wet dog shakes (WDS) produced by carbachol chloride (10 microgram/10 microliter, ICV) in rats. Reserpine, alpha-methyl-p-tyrosine and FLA 63 did not affect WDS, while diethyldithiocarbamic acid depressed it. Aceperone and yohimbine weakened shaking response to carbachol but phentolamine given ICV showed no effect on WDS. Propranolol and isoproterenol administered ICV did not significantly influence WDS. Apomorphine failed to affect WDS induced by carbachol. Pimozide and spiperone were also ineffective against WDS, but amphetamine and metoclopramide efficiently blocked it. Selective depletion of brain NA concentration considerably enhanced WDS, while selective depletion of brain DA concentration failed to affect it. These results suggest that carbachol-induced WDS behavior is under the inhibitory control of noradrenergic neurons.