Behavioral responses to intracerebroventricularly administered neurohypophyseal peptides in mice

Lysine vasopressin (LVP), arginine vasopressin, oxytocin, and arginine vasotocin administered intraventricularly (icv) to mice all provoked a dose-dependent behavioral response in the range 0.1 – 1.0 μg. This response included a pronounced hyperactivity, extensive foraging, increased grooming, and at higher doses, stereotyped scratching, squeaking, and occasional barrel rolling. The four hormones were all approximately equipotent. Desglycinamide lysine vasopressin and [desaminocys₁, D-Arg₈] vasopressin produced some of the characteristic behaviors, but were much less potent. While pretreatment of the animals with reserpine (5 mg/kg ip), haloperidol (0.5 mg/kg ip), or physostigmine (0.5 mg/kg ip) sedated the animals and attenuated the locomotion and grooming, these drugs did not substantially alter the characteristic behavioral responses to LVP. Pretreatment with α-methyl-p-tyrosine (400 mg/kg ip), p-chlorophenylalanine (320 mg/kg ip), 6-hydroxydopamine (100 μg icv), ergotamine (0.5 μg icv), ethoxolamide (52 ng icv), diphenhydramine (20 μg icv), prostaglondin F_2α (2 μg icv), or naloxone (1 mg/kg ip) did not alter the LVP-induced behaviors. None of these drugs or -amphetamine (0.5 to 20 mg/kg ip) or nicotine (0.1 or 1 μg icv) mimicked the behavioral effects of the hormones.     

Transport of sodium and potassium in intestinal epithelial cells

Transport properties of rabbit small intestinal mucosa were investigated $\text{in vitro}$ to characterize the process by which epithelial cells maintain normal Na and K gradients across the cell membrane. Active transport of Na from the cell proceeded at a faster rate in the presence of K; and active transport of K into the cell was stimulated by the presence of Na. Following preincubation at 0°C to reduce tissue K content, a greater transmural electrical potential difference (PD) and short-circuit current (I_sc) developed as the temperature was raised to 37°C if K was present in the bathing solution. The PD and I_sc, which generally reflect the rate of active Na transport in ileum under control conditions, increased immediately upon raising the K concentration in the serosal solution from 0 to 10 nM.The results present the first direct indication in mammalian intestine of an interdependence of the Na and K active transport processes which regulate the intracellular content of these cations.     

The genetic instabilities of the mating type locus in fission yeast

Summary Certain genetic instabilities of the mating type locus in the yeast Schizosaccharomyces pombe are interpreted in terms of transposition: Homothallic strains are characterized by two adjacent mating type genes (mat1 ^– mat2 ⁺) with sexually complementary functions. One of these genes (mat2 ⁺) is able to duplicate itself, and the duplicated copy maps at the position of mat1 ^–. The former function of mat1 ^– is lost (owing to insertion), and only becomes reactivated when the inserted sequence (mat1 ⁺) is again excised. Analyses of analogous instabilities expressed by the partially defective mutation mat2 ⁺-B102 have substantiated this transposition scheme.Homothallism is acribed to alternate and mutually exclusive activation of mat1 ^– or mat2 ⁺ genes.     

The condensed tannins of pasture legume species

Condensed tannins have been isolated from legume pasture species and purified by gel chromatography on Sephadex G-50 and LH-20 media. Molecular size di     

Preliminary observations on the birth and development ofPropithecus verreauxi to the age of six months

In this paper, preliminary observations are presented on the ontogency of one of the Malagasy prosimians,Propithecus verreauxi. Observations were carried out in the course of an eighteen-month study of the social organization and ecology of four, free-ranging groups. Parturition is described, together with data on the development of locomotor and feeding behavior, and on the changing nature of the infant's relationship with its mother and with other members of the group. The final section compares the results of this study with those of previous studies ofP. verreauxi and other lemur species. Tentative conclusions are drawn concerning aspects of social ontogeny inP. verreauxi and areas for future research are suggested which would clarify some of the remaining problems.     

In. vitro evaluation of corpus luteum function of cycling and pregnant rhesus monkeys: Progesterone production by dispersed luteal cells

Corpus luteum function in the cycling and the pregnant rhesus monkey (Macaca mulatta) was evaluated through short term $\text{in vitro}$ studies of progesterone production by suspensions of collagenase-dispersed luteal cells in the presence and absence of exogenous gonadotropin (human chortonic gonadotropin, HCG). Cells from mid-luteal phase of the menstrual cycle secreted progesterone, as measured by accumulation of this hormone in the incubation medium, and responded to the addition of 100 ng HCG/ml with a marked increase in progesterone secretion above basal level ($\text{63.7 ± 13.1}\text{versus}\text{24.7 ± 5.5}\text{ng progesterone}\text{/}\text{ml}\text{/5 × 10}{}^4\text{cells}\text{/ 3}\text{hr}\text{,}\text{X}\text{± S.E.,}\text{n}\text{= 6;}\text{p}\text{< 0.05}$). However, luteal cells from early pregnancy (23–26 days after fertilization) secreted significantly less progesterone than cells of the non-fertile menstrual cycle (3.6 ± 2.4 versus 24.7 ± 5.5 ng/ml/5 × 10⁴ cells/3 hr, n = 3; p < 0.05) and did not respond to HCG with enhanced secretion. By mid-pregnancy (108–118 days gestation) luteal cells exhibited partially renewed function, and near the time of parturition (163–166 days gestation) basal and HCG-stimulated progesterone secretion (30.2 ± 5.6 and 63.0 ± 13.0 ng/ml/5 × 10⁴ cells/3 hr, respectively; n = 3) was equivalent to that of cells from the luteal phase of the non-fertile menstrual cycle. The data suggest that following a period around the fourth week of gestation, when steroidogenic activity is markedly diminished, the corpus luteum of pregnancy progressively reacquires its functional capacity and at term exhibits gonadotropin-sensitive steroidogenesis similar to that of the corpus luteum of the menstrual cycle.     

A novel temperature-sensitive mammalian cell line exhibiting defective prophase progression

A temperature-sensitive mammalian cell line has been isolated which grows and divides normally at the permissive temperature of 33°C. When incubated at 39°C, the nonpermissive temperature, interphase cells continue to enter a prophase-like state. Chromatin-like material condenses and coalesces into dark-staining clumps rather than into discernible chromosomes. Disappearance of the nuclear boundary is observed, but re-formation of the boundary around the clumps fails to occur. Incorporation of labeled precursors reveals a decrease in protein synthesis which is accompanied by a slower decrease in DNA synthesis. Approximately 0.2% of the mutant cells revert in their capability of growth and cell division at 39°C. These “revertants” are found to contain a higher number of chromosomes. The isolation of this mutant is based on the initial observation that the cells become rounded at the nonpermissive temperature. The cell-rounding process characteristic of mitotic cells should serve as a useful marker in the isolation of mitotic mutants.     

Sex-differences in the Agonistic Behavior of Spiny-mice (Acomys cahirinus)

Observations of 8 groups each containing three adult spiny mice (Acomys cahirinus) revealed that instances of chasing and physical displacement were quite common, while fighting and biting were rarely observed. The relationships between the most frequent behavioral categories were presented in a correlation matrix. In a second, study, ♀♀ tested in their home cages were dominant over ♂♂ In the ♂♂ home cages, however, no differences in the frequency of ♀ vs. ♂ aggression were observed. More instances of aggression were observed in the cages of the ♀♀ than in the cages of the ♂♂.