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Twenty four castrated male, 6 intact male, and 11 intact female Hyla cinerea were injected subcutaneously with 25 μg arginine-vasotocin (AVT) and induced to call 1 h later in response to the playback of a conspecific mating call. Eighteen castrated males and 8 intact females were implanted 5 mg androgen pellets for 3 weeks prior to the neuropeptide(More)
Responses of auditory neurons in the torus semicircularis (TS) of Pleurodema thaul, a leptodactylid from Chile, to synthetic stimuli having diverse temporal patterns and to digitized advertisement calls of P. thaul and three sympatric species, were recorded to investigate their temporal response selectivities. The advertisement call of this species consists(More)
Variation of the amplification effect of burrows of the leptodactylid frog Eupsophus emiliopugini on conspecific calls generated externally was investigated. Advertisement calls broadcast through a loudspeaker placed in the vicinity of a burrow were monitored with small microphones positioned inside and outside the cavity. For 150 presentations of calls of(More)
Addition of specific antigen to the isolated atria of sensitized guinea pigs and of histamine to those of nonsensitized animals resulted in an increase of both frequency and amplitude of contraction and in the appearance of rhythmic activity in the isolated left atrium. On a quantitative basis the anaphylactic response looks like the effects of histamine in(More)
Sound pressure levels and the spectral structure of the advertisement calls of five species of frogs from the South American temperate austral forest were analyzed. Males of Eupsophus emiliopugini, Batrachyla antartandica and B. leptopus call from the ground in bogs, while males of Hylorina sylvatica and Pleurodema thaul call from the water surface in(More)
To study the effect of halothane on the coronary circulation, the circumflex diastolic coronary vascular resistance was measured in the working heart and total mean coronary resistance (TCR) in the isolated nonworking heart of the dog during administration of 100 per cent oxygen and during administration of 2--3 per cent halothane in oxygen. In the working(More)
In 15 heart-lung preparations, modified to retain either the head or body circulation, the performance of the heart was tested during the inhalation of either 5% oxygen or pure nitrogen. Two mechanisms were demonstrated to participate in cardiac stimulation: a) stimulation of aortic body chemoreceptors which caused an increase in right ventricular segment(More)
We investigated the response selectivities of single auditory neurons in the torus semicircularis of Batrachyla antartandica (a leptodactylid from southern Chile) to synthetic stimuli having diverse temporal structures. The advertisement call for this species is characterized by a long sequence of brief sound pulses having a dominant frequency of about 2000(More)
Sound stimulates the tympanic membrane (TM) of anuran amphibians through multiple, poorly understood pathways. It is conceivable that interactions between the internal and external inputs to the TM contribute to the nonlinear effects that noise is known to produce at higher levels of the auditory pathway. To explore this issue, we conducted measurements of(More)