Albert R. Dawe

Hibernation Induced in Ground Squirrels by Blood Transfusion

Natural mammalian hibernation was continuously maintained under laboratory conditions throughout spring and summer seasons in a colony of thirteen-lined ground squirrels by serial transfusional passage of blood from hibernations animals to active animals. This procedure successfully produced hibernation in animals until late summer, at which time naturally occurring (spontaneous) hibernations occurred in the colony, thus terminating the experiment.

Several blood and circulatory changes in the hibernation of the 13-lined ground squirrel, Citellus tridecemlineatus

A monitoring device for use in measuring earth potentials, including a hub carried by a handle unit and having a plurality of spokes extending therefrom. Each spoke has an electrolytic solution cell on its outer end, into which a spoke-mounted electrode extends. The outer end of the cell has a porous tip mounted thereon, which is wetted by the solution and engages the earth. The spokes and the hub are made of conductive material, and a brush-type electrical pickup on the handle unit engages the hub for transmitting signals detected by the wetted porous tips as they progressively engage the earth when the device is rolled along.

The blood-borne “trigger” for natural mammalian hibernation in the 13-lined ground squirrel and the woodchuck☆

A blood-borne trigger for natural mammalian hibernation is described and details of the conditions necessary for its successful utilization are enumerated: 1. 1. It is present in serum and cells of hibernation blood both in ground squirrels (Citellus tridecemlineatus) and woodchicks (Marmota monax). 2. 2. It acts intra and interspecifically insofar as appropriate hibernation serum of 13-lined ground squirrel when transfused can trigger hibernation in other ground squirrels of the same species, and appropriate hibernation serum of woodchucks can similarly trigger hibernation in both woodchucks and in 13-lined ground squirrels. Withdrawal, preparation, and transfusions follow a careful technique outlined in References 1 and 2. 3. 3. The whole blood, serum, and cells retain the hibernation-inducing power for at least 6 months whether kept at freezer temperature (−15 °C) or liquid nitrogen temperature (−196 °C). 4. 4. The trigger is effective whether used as serum or as dialyzate of that serum (prepared as described). The nondialyzed residue was not effective, and evidence has been found which indicates that an antitrigger may be present in that residue. 5. 5. Cold adaptation may be contraindicated for trigger effectiveness. 6. 6. The titer of trigger in a donors blood evidently increases as a bout of hibernation lengthens. This is noted by the fact that trigger taken from a donor long in hibernation induces hibernation more rapidly in recipients than does trigger from a donor in a short bout of hibernation. 7. 7. Trigger manifests its effect in winter whether a recipient animal is placed in a colddark or a warm window-lit room. (Trigger effect in a warm window-lit room in a nonhibernating season has not as yet been studied.) 8. 8. Trigger has not been found either in the blood of active or of aroused animals. Thus, effective material is not circumscribed by the expression “winter blood,” but rather by the expression “hibernation blood.” 9. 9. Female animals in all cases are more effective recipients than males, whereas neither sex is a better donor. 10. 10. Recipient animals receiving a trigger and maintained in cold-dark rooms will not show seasonal reversal, rather, have been observed to show bouts of hibernation intermittently for as long as 2 years. They seemingly do not return to the active state. A theoretical approach to hibernation induction is advanced which holds that the trigger is a small molecular material (SM) found in blood taken in hibernation. It is excreted, complexed, and/or metabolized in the arousing process. It may complex with another blood-borne trigger-inhibitor (LM) to form a complex (CM). The entire circannual cycle of hibernation can be related to relative concentrations of SM, LM, and CM. Speculation is further set forth as to hibernation of tissue as contrasted to hibernation of animals. This notion was presaged by others, notably by Lyman, Kayser, and Suomalainen. As Lyman stated (7) “… entrance into hibernation is more than the abandonment of the warm-blooded state.”

Summer hibernation of infant (six week old) 13-lined ground squirrels, Citellus tridecemlineatus

Abstract In an endeavor to more clearly define the physiological action of hibernation trigger (previously identified by the authors) an experiment was devised using infant ground squirrels. In one case, pregnant ground squirrel mothers were transfused intravenously with cold dialysate of serum of hibernating woodchuck, and in another case, infant (1 week to 3 week) squirrels were transfused intraperitoneally with the same material. When isolated and placed in a cold room (15 °C) at 6 weeks post partum , both the infant born of the transfused mothers, as well as the infant which has been transfused directly, hibernated in the summer. This was in contrast to controls of several kind, i.e., animals not injected, or receiving active or arousing woodchuck serum or heat-treated hibernation serum. Some details for a theory, which had been advanced in a previous article (4), were essentially substantiated by this experiment. It is our belief that this represents the first time mammalian hibernation has been observed in infant hibernators.

Electrical and mechanical sustained automaticity of the isolated heart of the 13-lined ground squirrel: Both circannually and arousing from hibernation

Abstract 1. 1. A unique method is described for monitoring the electrical and mechanical performance of the isolated heart at 5° C. The cardiac tissue alone provides energy for sustained activity without perfusion or oxygenation. 2. 2. Isolated hearts from 239 hibernating and active ground squirrels demonstrated: 1. (a) The resistance to the cold of the isolated myocardium (resulting in longer sustained automaticity) increases as a circannual event. 2. (b) Hearts isolated from animals hibernating naturally in winter, or induced to hibernate in summer, consistently performed electrically for 8 or more hours in the cold, whereas the hearts of active animals stopped after 1 2 –3 hr depending on the season.