Heart Rate and Defecation Frequency as Measures of Rodent Emotionality.

Abstract

To assess the relationship between heart rate and defecation frequency as comparable measures of emotionality, both were recorded simultaneously from albino rats in a novel environment and in the home cage. Subgroups receiving different numbers of trials were used under both environmental conditions to distinguish the possible effects of distribution of trials and age. Heart rate and defecation frequency were higher in the novel environment. Intertrial adaptation to the novel environment over 30 successive test days appeared in defecation frequency but not in heart rate. Intratrial adaptation appeared in heart rate. Heart rate and defecation frequencies were not significantly correlated, either for individual Ss or groups. Heart rate was higher in females than males, but defecation frequency did not vary with sex.

Individual Differences in Autonomic Responsivity in the Adult Rat

“…Differences in heart-rate levels between the sexes have been previously noted (14,17). The present experiment confirms that after handling, females have higher heart rates than males, but do not differ in baselevel heart rate after adaptation.…”

“…Snowdon et al (17) found a negative relationship (-0.59) between the two variables when animals were tested in the open field. The present investigation does not support this finding and seems consonant with the view expressed by Candland et al (14) that, although heart rate and defecation frequency are modified as a function of environmental change in a stable fashion, they change in different ways and are not significantly correlated with each other.…”

“…The procedure followed has been used by several previous workers to record heart rate (13,14) . Animals were anesthetized under light ether anesthesia, and stainless steel wire (diameter 0.015 inches) inserted through a hypodermic syringe needle under a fold in the animal's skin.…”

Two tests of a fear-motivated theory of exploration

“…Results from other experiments are reasonably consistent with this result, even though these studies used rats of different strains than that used in this experiment. For example, Candland et al (1967) using rats of the strain Carnsworth CFE found no sex differences in defecation behavior, but female rats had a higher heart rate than did male rats. Snowden et al (1964), using Wistar rats, found that the females had a higher heart rate than the males.…”

Analgesic, Heart Rate, and Temperature Effects of Δ⁸-THC during Acute and Chronic Administration to Conscious Rats

“…Heart-rate change in rats is a sensitive index of arousal and of 'affective' states produced by environmental stimuli that modify behavior (5,9), and might signal, as well, the kind of discriminable interna] state induced pharmacologically by THC (19) that can act to punish strongly preferred behaviors (7).…”