Innervation of the Lung of the Australian Snake-necked Tortoise, Chelodina Longicollis

1. The innervation of the smooth muscle of the lung of the Australian snake-necked tortoise. Chelodina longicollis, was investigated using in vitro pharmacological techniques. 2. The smooth muscle bands of the lung were innervated by cholinergic excitatory fibres and non-cholinergic, non-adrenergic, excitatory fibres. 3. Inhibitory responses of the smooth muscle bands to transmural stimulation occurred infrequently following excitatory responses and the neurotransmitter(s) involved were not determined. Noradrenaline caused a beta-adrenoceptor mediated relaxation of the smooth muscle bands. 4. The excitatory response caused by cholinergic and non-cholinergic, non-adrenergic fibres was tetrodotoxin resistant.