Quantitative studies on the mating system of opium poppy (Papaver somniferum L.)

Nearly 400 individuals at two locations and over a number of years were crossed and subsequently scored for selfing versus outcrossing in eight monohybrid populations of opium poppy (Papaver somniferum). Two different marker loci, petal colour (R/r) and capsule size (B/b) were used to determine the male gametes that had effected fertilizations in F2 recessives (rr and bb). The estimates of the outcrossing parameter α were found to vary with year, location and for the marker locus used (α range: 0.0988-0.3704). Study of two dihybrid crosses involving the two loci simultaneously, further confirmed that outcrossing at the R/r locus was significantly greater than that at the B/b locus. The nature of the outcrossing was, in general, nonrandom. Selfmg predominated in this species; however, there was a high frequency of natural outcrossing for generating variations in P. somniferum.

Intrapartum clinical, sonographic, and parous patients' estimates of newborn birth weight

The accuracy of estimating birth weight clinically, sonographically (using femur length and abdominal circumference), and by maternal prediction was studied prospectively in 106 term parous women who were in active labor. Estimates of birth weight by these women had lower standardized error (86.8 +/- 78.0 g/kg) than either clinical estimates (90.2 +/- 84.8 g/kg) or sonographically derived estimates (155.8 +/- 118.0 g/kg) of birth weight (P = not significant). Maternal estimates of birth weight were within +/- 10% of the actual weight in 69.8%, compared with 66.1% for clinical estimates and 42.4% for sonography. A term parous woman in labor can predict the birth weight with accuracy comparable to a clinical estimation by a physician or a sonographic estimate based on infant measurements.

Amniotic fluid index before and after amnioinfusion of a fixed volume of normal saline

Twenty-one women at term, with an amniotic fluid index (AFI) less than or equal to 5.0 cm and intact membranes, underwent an artificial amniotomy and transcervical amnioinfusion of 250 mL of normal saline at room temperature. The mean (+/- SD) cervical dilation at the time of the transcervical amnioinfusion was 2.6 +/- 1.3 cm (range, 1-6). The mean AFI prior to the amnioinfusion was 3.0 +/- 1.49 cm (range, 0-4.7). The mean AFI after the amnioinfusion was 8.9 +/- 2.9 cm (range, 5.1-14.3). A mean change in the AFI of 5.8 +/- 2.6 cm (range, 0.9-10.6) was noted. Among patients with AFI less than or equal to 5.0 cm and intact membranes, amnioinfusion of 250 mL of normal saline seems to be a safe and simple way to increase the AFI to greater than 5.0 cm.

Possible existence of dopaminergic receptors on cholinergic nerve terminals in the guinea-pig Auerbach's plexus

In the Auerbach's plexus of guinea-pig ileum lower concentrations of oxotremorine (Oxo-T) produced an increase, whereas higher concentrations of Oxo-T caused inhibition of evoked acetylcholine (ACh) release, measured by bioassay using dorsal muscle of leech. Dopamine inhibited the increase in evoked release of ACh induced by Oxo-T as a function of its concentration and this inhibitory effect was nullified in presence of pimozide, the dopamine receptor antagonist. The results demonstrate existence of presynaptic dopamine receptors having inhibitory influence on excitatory presynaptic muscarinic receptors on regulation of ACh release. However, no physiological role of dopamine could be observed on ACh release in this preparation.

5-Hydroxytryptamine in the phrenic nerve diaphragm: evidence for its existence and release

Evidence is presented for the existence of 5-hydroxytryptamine (5-HT) within the phrenic nerve of the rat and its release following electrical stimulation. Contents of 5-HT and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA) in the phrenic nerve and the indoleamine released into the bathing fluid were estimated fluorimetrically after isolation on Sephadex G-10 and/or solvent-solvent extraction. Bioassays of 5-HT were done on rat fundus strip. The phrenic nerve and the end-plate zone contains high levels of 5-HT (1.9 micrograms/g wet weight) and 5-HIAA (1.5 micrograms/g wet weight). The resting release of around 1 ng 5-HT/diaphragm/min was enhanced by 50% (1.5 ng 5-HT/diaphragm/min) upon supramaximal (2-4 V) electrical stimulation of 5 Hz. Phrenic nerve diaphragm prepared from the denervated and p-chlorophenylalanine (300 mg/kg/day i.p. for 3 days) treated rats failed to release 5-HT confirming the neuronal origin and the identity of the indoleamine respectively. Furthermore, methysergide, an antagonist of 5-HT in rat fundus strip, blocked the response obtained by the sample on it. A modulatory role of 5-HT in the phrenic nerve diaphragm of the rat is envisaged from the present study.

Alpha 2-antagonistic effect of N-carbamoyl-2-(2,6-dichlorophenyl) acetamidine hydrochloride (LON-954)

The effect of N-carbamoyl-2-(2,6-dichlorophenyl) acetamidine hydrochloride (LON-954) on alpha 2-adrenoceptors was studied in in vivo and in vitro preparations. Like yohimbine, LON-954 antagonised the clonidine-induced inhibition of twitch responses in the Auerbach's plexus of guinea pig ileum and rat vas deferens preparations. It also reversed the anti-convulsant effect of clonidine on pentylenetetrazol (PTZ)-induced convulsions in the rat, a property shared by yohimbine. However LON-954 failed to prevent the hypothermic response to clonidine in mice. The dissimilarity in action of LON-954 and yohimbine on clonidine-induced hypothermia could be due to the fact that the anticlonidine effect of yohimbine on hypothermia is mediated through its antiserotonin action. The results indicate that LON-954 acts as an alpha 2-antagonist both centrally and peripherally.

Possible functional role of substance P on the mammalian motor nerve terminals

The effect of substance P (sP) on mammalian skeletal myoneural transmission was studied employing innervated and denervated isolated rat diaphragm preparations. sP at a concentration of 3.7 nM facilitated the indirect twitch responses of the rat diaphragm and antagonised the paralytic effect of d-tubocurarine (d-Tc). sP failed to affect the direct twitch responses as well as the contractures induced by acetylcholine (ACh) and potassium chloride (KCl) in the denervated diaphragm. The amount of ACh released into the bathing medium in response to tetanic stimulation of the phrenic nerve was doubled in presence of sP. The study illustrates a presynaptic facilitatory involvement of sP on mammalian myoneural transmission.