The initiation of diving apnoea in the frog, Rana pipiens

1976 ◽  
Vol 64 (1) ◽  
pp. 25-38
Author(s):  
N. H. West ◽  
D. R. Jones
Keyword(s):  
Electrical Stimulation ◽  
Water Level ◽  
Rana Pipiens ◽  
Buccal Cavity ◽  
Respiratory Muscles ◽  
Normal Pattern ◽  
Water Head ◽  
Response To Water ◽  
Water Meniscus ◽  
Stimulation Of

1. Diving apnoea in Rana pipiens was initiated by submerging the external nares. As the water level was raised above the frog, both buccal and lung pressure increased by an amount corresponding to the water head. During submergence the external nares remained closed, although the apnoeic period was punctuated by ventilation movements which moved gas between the lungs and buccal cavity. 2. Bilateral section of the ophthalmic nerves did not alter the normal pattern of ventilation in air, although it often resulted in the intake of water into the buccal cavity on submergence. Introduction of water into the buccal cavity, either naturally as in denervates or by injection through a catheter in intact frogs, triggered sustained electromyographical activity in some respiratory muscles. 3. Electroneurograms recorded from the cut peripheral end of an ophthalmic nerve showed that receptors in the external narial region were stimulated by movement of a water meniscus across them. Activity could also be recorded in the ophthalmic nerve in response to water flow past the submerged nares. Punctate stimulation of the narial region confirmed that these receptors were mechanosensitive. 4. Bilateral electrical stimulation of the central ends of cut ophthalmic nerves in lightly anaesthetized frogs caused apnoea with a latency of less than 200 ms. The external nares remained closed throughout the period of stimulation although buccal pressure events, resembling underwater ventilation movements, occurred when stimulation was prolonged.

Breathing movements in the frog Rana pipiens. I. The mechanical events associated with lung and buccal ventilation

1975 ◽  
Vol 53 (3) ◽  
pp. 332-344 ◽  
Author(s):  
N. H. West ◽  
D. R. Jones
Keyword(s):  
Rana Pipiens ◽  
Buccal Cavity ◽  
Lung Ventilation ◽  
Cavity Pressure ◽  
Normal Pattern ◽  
Large Pressure ◽  
Dilator Muscle ◽  
Recovery Stroke ◽  
Two Phases ◽  
Low Pressures

The normal pattern of breathing movements in Rana pipiens has been studied by recording pressure and volume changes in the buccal cavity and lungs, and electromyograms from the muscles involved in this activity. Two types of breathing movement were obtained, one concerned with ventilation of the buccal cavity (buccal cycles) and the other with lung ventilation (lung cycles). Only in the latter type of movement were the nares and glottis actively involved. During buccal cycles the nares remained open and the glottis closed, so although excursions of the buccal floor were some two-thirds of the magnitude of those occurring during lung cycles, only low pressures were generated. The onset of a lung cycle was signalled by activity in the laryngeal dilator muscle. When the glottis opened, lung pressure and volume decreased, and buccal cavity pressure and volume increased. After closure of the nares, the buccal floor was rapidly elevated by the activity of the breathing muscles and air was forced into the lungs from the buccal cavity. At peak pressure in the lungs and buccal cavity the glottis closed and nares opened. The recovery stroke of the buccal pump was passive. No evidence was found for large pressure differentials between the buccal cavity and lungs when the glottis was open, and air-flow recordings at the external nares showed two phases of flow during each buccal cycle and four phases with each lung ventilation cycle.

Preoptic Activation of Frog Mating Behavior

Behaviour ◽  
1967 ◽  
Vol 30 (2-3) ◽  
pp. 239-257 ◽  
Author(s):  
Robert S. Schmidt
Keyword(s):  
Electrical Stimulation ◽  
Mating Behavior ◽  
Rana Pipiens ◽  
Preoptic Area ◽  
Preoptic Nucleus ◽  
Bufo Americanus ◽  
Electrode Holder ◽  
Tree Frogs ◽  
Stimulation Of

AbstractThe effects of preoptic lesions on mating calling and mate orientation were studied in Rana pipiens and several species of tree frogs (Hylidae). Mating calling was evoked by electrical stimulation of the preoptic area of Rana pipiens and Bufo americanus. A new chronic electrode holder is described. It is concluded that the region of the dorsal magnocellular preoptic nucleus is needed for mate orientation and that the region of the ventral magnocellular preoptic nucleus is needed for mating calling. It is suggested that these preoptic regions may act mainly as activators of more posterior "centers". Mating calling may have evolved through the origin of connections between pre-existing preoptic activators and a pre-existing release calling "center", rather than through the origin of a new mating calling "center".

scholarly journals Radiocalcium Release by Stimulated and Potassium-Treated Sartorius Muscles of the Frog

1960 ◽  
Vol 43 (3) ◽  
pp. 481-493 ◽  
Author(s):  
A. M. Shanes ◽  
C. P. Bianchi
Keyword(s):  
Electrical Stimulation ◽  
Time Course ◽  
Rana Pipiens ◽  
Calcium Release ◽  
Sartorius Muscle ◽  
Entry And Exit ◽  
Potassium Depolarization ◽  
Rate Of Escape ◽  
The Individual ◽  
Stimulation Of

Stimulation of frog (Rana pipiens) sartorius muscle accelerates release of Ca45, but only during the period of stimulation. No appreciable difference is obtained in the calcium released per impulse whether stimulation is at a rate of 20/sec. or 0.5/sec. However, prior stimulation may appreciably increase the loss per impulse. In unfatigued muscles, the minimum amount of calcium liberated during an isotonic twitch is estimated to be about that previously calculated to enter, viz. 0.2 µµmole/cm2. The time course of radiocalcium release during potassium depolarization depends on the nature of the contracture. When contracture is isometric, the rate of escape is doubled and declines only slowly; if isotonic, the rate is quadrupled but declines in a few minutes to a level maintained at about double that before potassium. The minimal calcium release during the first 10 minutes of potassium treatment is estimated to be about the same in both cases and about one-half to one-third the uptake. This, and especially the close equality of calcium entry and exit during electrical stimulation, are pointed out as not necessarily inconsistent with a transitory net entry of calcium, comparable to the influx, into restricted regions of the individual fibers.

scholarly journals The respiratory system biomechanical homeostasis and its maintenance mechanisms in normal conditions and at obstructive pulmonary diseases

2007 ◽  
Vol 6 (1) ◽  
pp. 13-38
Author(s):  
A. I. Karzilov
Keyword(s):  
Electrical Stimulation ◽  
Respiratory System ◽  
Respiratory Muscles ◽  
Pulmonary Diseases ◽  
Elastic Recoil ◽  
Inspiratory Capacity ◽  
Surfactant Complex ◽  
Biomechanical Parameters ◽  
Healthy Persons ◽  
Stimulation Of

Parameters of breathing biomechanics in healthy persons (n = 20), patients with bronchial asthma (n = 30) and chronic obstruc-tive pulmonary disease (n = 30) are analyzed during electrical stimulation of the diaphragm. Methodology of homeostatic parame-ters searching and their classification is offered. Descriptive and comparative analyses are performed. Homeostatic parameters of biomechanics describing the condition of elastic and non -elastic properties of respiratory system, of respiratory muscles, of general pulmonary hysteresis, breathing regulation are differentiated. Basic homeostatic parameter is the ratio of inspiratory capacity to the lungs elastic recoil. The model of lungs with the biomechanical buffer and retractive-elastic- surfactant complex of lungs is offered. Biomechanical homeostasis idea of respiratory system as ability of an organism to support in dynamics balance normal and patho-logical conditions essentially important for preservation of respiratory system biomechanical parameters in admissible limits is for-mulated.

Breathing movements in the frog Rana pipiens. II. The power output and efficiency of breathing

1975 ◽  
Vol 53 (3) ◽  
pp. 345-353 ◽  
Author(s):  
N. H. West ◽  
D. R. Jones
Keyword(s):  
Body Weight ◽  
Power Output ◽  
Rana Pipiens ◽  
Buccal Cavity ◽  
Respiratory Muscles ◽  
Lung Ventilation ◽  
Pressure Change ◽  
Mechanical Efficiency ◽  
Lung Inflation ◽  
Anticlockwise Direction

The work done by the buccal cavity during buccal and lung ventilation cycles has been estimated from measurement of the area enclosed by pressure–volume loops for each cycle. The loops cycled in an anticlockwise direction with respect to time during buccal cycles. On the other hand, pressure–volume loops from the lungs cycled clockwise, showing that work was being done on the lungs by the buccal pump. Inflation and deflation of the buccal cavity from a syringe, in curarized frogs, gave a clockwise loop enclosing about 5.5–6.5% of the area enclosed by a naturally generated loop of the same pressure and volume. However, inflation and deflation of the lungs gave a loop which enclosed an area virtually identical with that obtained from a normally generated sequence of lung inflation and deflation. The power output of the buccal pump was directly proportional to body weight, the major determinant of the former being the larger buccal volume rather than pressure change as body weight increased. The mechanical efficiency of the buccal pump varied from 0.4% to 16.2%, efficiency increasing with increased power output over most of the physiological range. Mean efficiency of all buccal movements was calculated to be 8% and, at this value of efficiency, oxygen consumption of the respiratory muscles was 0.89 ml O2 100 g−1 min−1. In Rana pipiens at rest the oxygen cost of breathing appears to be about 5% of the total resting metabolism.

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