>Since underwater submergence is the usual stimulus inducing the DR in awake animals, many investigators performed “forced” submersions, where the animals were tethered on boards or placed in cages and dunked underwater (54, 59, 94, 111, 113, 120, 125, 130, 131, 147, 185, 213, 216). Many of these studies noted the hemodynamic responses were subtly dissimilar to voluntary submersions (94, 111, 162, 244). HR generally reaches a nadir quickly in forced submersions and remains depressed until the animal surfaces. However, the bradycardia of aquatic mammals diving voluntarily and with but moderate exercise is more variable and less intense than that seen in forced diving (54, 111, 119, 162, 185), but the bradycardia of involuntarily dunked rats is not different than voluntarily diving rats (185). Although such differences suggest neural control beyond the level of reflex and implicate suprabulbar control in large aquatic mammals, it suggests the response in the rodent is more reflexive in nature.
I wish I studied biology instead of chemical engineering, this sounds hella fun.
