ABSTRACT
The enzymes in perilymph of the inner ear scala and within fluid filling the middle ear cavity were investigated in the fetal guinea pig near term. Perilymph lactic dehydrogenase (LDH) exhibited differential activity between fetal scalae vestibuli and tympani, and LDH, aldolase, phosphohexose isomerase and creatine phosphokinase in perilymph of particular fetal scalae were elevated in activity in activity in comparison to corresponding maternal values. Moreover, LDH displayed different isozyme patterns for antenatal and gravid perilymph. In the middle ear fluid, all of the above enzymes were encountered but varied somewhat from the quantities determined for either prenatal perilymph or maternal serum. After gravid guinea pigs were exposed to a tone of 4 kHz, 100 dB SPL for 2 hours, LDH of the fetal middle ear fluid was reduced in activity 24 hours later. The metabolic significance of the fetal distinctions in the ear fluids and the clinical implications of the current work are discussed.
Subject(s)
Creatine Kinase/metabolism , Ear, Inner/enzymology , Ear, Middle/enzymology , Fructose-Bisphosphate Aldolase/metabolism , Glucose-6-Phosphate Isomerase/metabolism , L-Lactate Dehydrogenase/metabolism , Labyrinthine Fluids/enzymology , Acoustic Stimulation , Animals , Ear, Inner/embryology , Ear, Middle/embryology , Female , Guinea Pigs , Perilymph/enzymology , PregnancyABSTRACT
Lactic dehydrogenase (LDH) was determined in the fluids of the inner ear scalae and the middle ear cavity of fetal guinea pigs near term. Scalar dissimilarities in prenatal perilymph and distinctions between fetal and maternal perilymph suggest functional differentiation between the antenatal scalae vestibuli and tympani, elevated glycolytic activity in the prenatal vestibular channel and primarily aerobic processes in fetal perilymph although anaerobic metabolism is also evident. Disparities between fetal middle ear fluid and prenatal perilymph as well as maternal serum indicate that the former medium is probably not directly derived from either of the latter sources. After experimental treatment consisting of the presentation of high-intensity sound to gravid animals, the total LDH activity of the fetal middle ear fluid decreased.
Subject(s)
Acoustic Stimulation , L-Lactate Dehydrogenase/metabolism , Labyrinthine Fluids/enzymology , Animals , Female , Fetus/enzymology , Guinea Pigs , Perilymph/enzymology , PregnancyABSTRACT
The effects of gonadectomy and hormonal treatment upon such emotional behavior as discriminated lever-press avoidance and poke activity were examined in the rat. Gonadectomy at 2 mo of age significantly increased the avoidance of female animals but did not affect those of males or the poke performance of either sex. High, multiple, subcutaneous injections of estradiol benzoate (125 mug/kg), progesterone (80 mg/kg) or their combination led to significant declines in avoidance behavior among females spayed at 2 mo of age. Other significant findings included a sex difference in poke performance where intact females, compared to intact males, executed more responses. Significant decrements in poke behavior were also observed for all subjects, regardless of sex, during testing and from one session to the next.
Subject(s)
Avoidance Learning/drug effects , Behavior, Animal/drug effects , Castration , Gonadal Steroid Hormones/pharmacology , Ovary/physiology , Testis/physiology , Animals , Estradiol/pharmacology , Exploratory Behavior/drug effects , Female , Male , Progesterone/pharmacology , Rats , Sex Factors , Testosterone/pharmacology , Time FactorsABSTRACT
Guinea pigs were exposed to sound varying from 2 to 8 kHz in frequency and 80-100 dB (SPL) in intensity for periods of 1 hr. The biochemical parameters, glucose, sodium, total protein, and the glycolytic enzymes, aldolase, phosphohexose isomerase, and total LDH as well as isozymes of the latter were ascertained for blood serum, perilymph, and, in some instances, cerebrospinal fluid. The three enzymes occurred at lower levels in perilymph as compared to blood serum. Except for a small difference in serum total protein, sound presentation incurred no significant effect on any of the above parameters. Definite differences in several metabolites were discerned for perilymph sampled according to scala and which were independent of the respective acoustical treatments. Thus, as compared to the scale tympani, the scala vestibuli perilymph displayed a higher glucose content and a diminished total LDH level and of the latter isozymes, LDH(1) ranged lower and LDH(2), higher. As further evidence pointing to cerebrospinal fluid as the possible origin of perilymph, similarities in glucose contents and LDH isozyme patterns were noted for both fluids.
