Thompson R R, Dickinson P S, Rose J D, Dakin K A, Civiello G M, Segerdahl A, Bartlett R
Neuroscience Program, Bowdoin College, Brunswick, ME 04011, USA.
Proc Biol Sci. 2008 Jul 22;275(1643):1685-93. doi: 10.1098/rspb.2008.0207.
We tested whether the sex pheromones that stimulate courtship clasping in male roughskin newts do so, at least in part, by amplifying the somatosensory signals that directly trigger the motor pattern associated with clasping and, if so, whether that amplification is dependent on endogenous vasotocin (VT). Female olfactory stimuli increased the number of action potentials recorded in the medulla of males in response to tactile stimulation of the cloaca, which triggers the clasp motor reflex, as well as to tactile stimulation of the snout and hindlimb. That enhancement was blocked by exposing the medulla to a V1a receptor antagonist before pheromone exposure. However, the antagonist did not affect medullary responses to tactile stimuli in the absence of pheromone exposure, suggesting that pheromones amplify somatosensory signals by inducing endogenous VT release. The ability of VT to couple sensory systems together in response to social stimulation could allow this peptide to induce variable behavioural outcomes, depending on the immediate context of the social interaction and thus on the nature of the associated stimuli that are amplified. If widespread in vertebrates, this mechanism could account for some of the behavioural variability associated with this and related peptides both within and across species.
我们测试了刺激雄性糙皮蝾螈求偶抱合行为的性信息素是否至少部分是通过放大直接触发与抱合相关的运动模式的体感信号来实现的，如果是这样，这种放大是否依赖于内源性血管紧张素（VT）。雌性嗅觉刺激增加了雄性延髓中记录到的动作电位数量，这些动作电位是对泄殖腔的触觉刺激（触发抱合运动反射）以及对吻部和后肢的触觉刺激的反应。在暴露于信息素之前，将延髓暴露于V1a受体拮抗剂可阻断这种增强作用。然而，在没有信息素暴露的情况下，拮抗剂并不影响延髓对触觉刺激的反应，这表明信息素通过诱导内源性VT释放来放大体感信号。VT在社交刺激下将感觉系统耦合在一起的能力可能使这种肽根据社交互动的即时背景以及因此根据被放大的相关刺激的性质诱导可变的行为结果。如果这种机制在脊椎动物中广泛存在，那么它可以解释与这种肽和相关肽在物种内和物种间相关的一些行为变异性。
