01930nas a2200181   4500008004100000245009600041210006900137260000800206300001200214490000800226520137800234100002301612700001801635700001601653700001701669700001801686856004401704       2004                        eng d00aMechanisms and significance of reduced activity and responsiveness in resting frog tadpoles0 aMechanisms and significance of reduced activity and responsivene  cMar  a1113-250 v2073 aHatchling Xenopus laevis tadpoles spend most of their time attached to objects or the water surface by mucus secreted by a gland on the head. While attached, swimming activity and responsiveness to swim-initiating stimuli are reduced over long periods of time. We have investigated the mechanisms and significance of this apparent long-term inhibition. In behavioural experiments we show, firstly, that innervation of the cement gland and GABA(A)-mediated inhibition are necessary for attachment to reduce responsiveness, and secondly, that denervation of the cement gland increases tadpole activity and increases their predation by damselfly nymphs (Zygoptera). To investigate the neuronal pathway from the cement gland to GABA(A) inhibition, we have devised an immobilized, inverted tadpole preparation where a weight attached to the mucus simulates the force as it hangs. Simulated attachment reduces responsiveness and spontaneous fictive swimming activity. We have recorded the activity and responses of trigeminal neurons innervating the cement gland. They are spontaneously active and simulating attachment results in a sustained increase in this activity. We propose that hanging from a mucus strand increases firing in cement gland afferents. This leads to tonic GABA inhibition that reduces tadpole activity and responses, and leads to fewer attacks by predators.1 aLambert, Thomas, D1 aHoward, Jenny1 aPlant, Andy1 aSoffe, Steve1 aRoberts, Alan  uhttps://odonatas.myspecies.info/node/57