Pharmacological studies on Puerariae Flos. IV: Effects of Pueraria thomsonii dried flower extracts on blood ethanol and acetaldehyde levels in humans.

We investigated the effects of extracts from the dried flower of Pueraria thomsonii on blood ethanol and acetaldehyde levels in humans consuming alcoholic beverages. The extracts of Pueraria thomsonii had no influence on blood ethanol and acetaldehyde concentration in humans. However, the extracts increased the elimination rate constant of blood acetaldehyde, although they had no effect on the elimination of blood ethanol in humans. These results suggest that Pueraria thomsonii promotes the elimination of blood acetaldehyde in humans. The present study clinically suggests that a modest stimulatory effect of Pueraria thomsonii on the elimination of blood acetaldehyde may passively mitigate acetaldehyde toxicity, such as flushing, palpitation, headache, etc., associated with excessive alcohol intake.

Hypothalamic region facilitating shivering in rats.

Although the posterior part of the hypothalamus has long been considered important for thermoregulatory shivering, it is unknown whether the neurons there or the passing fibers are implicated in the response. Exposure of urethane-anesthetized rats to cold (15-21 degrees C) elicits shivering. An injection of muscimol (0.5 mM), a GABA(A) receptor agonist, into the medial part of the hypothalamus, including the dorsomedial and posterior nuclei, suppressed the cold-induced shivering. This result suggests that neurons having an excitatory effect on shivering are in this region of the hypothalamus.

PKCtheta II, a new isoform of protein kinase C specifically expressed in the seminiferous tubules of mouse testis.

Protein kinase C (PKC) theta, a Ca(2+)-independent isoform of PKC, has been known to be expressed in skeletal muscle and T cells. In the present study, we isolated and characterized a smaller transcript expressed in the mouse testis, the cDNA of which is referred hereafter as PKCthetaII and the original PKCtheta as PKCthetaI. The cDNA clone of PKCthetaII has 2184 base pairs and 464 amino acids in the possible open reading frame, consisting of the 5' unique sequence of 20 amino acids and the PKCthetaI sequence of 444 amino acids. Genomic DNA analysis revealed that transcription of PKCthetaII is initiated from the PKCthetaII-specific exon, which is located between exons 7 and 8 of the PKCtheta gene, indicating that alternative splicing is the mechanism by which PKCthetaII is generated. PKCthetaII is expressed exclusively in the testis in an age-dependent manner with sexual maturation. In situ hybridization and reverse transcription-polymerase chain reaction of microdissected tissues clearly demonstrated that PKCthetaII is expressed in the seminiferous tubules of the mouse testis. Consistent with its molecular structure lacking the C1 regulatory domain, PKCthetaII is constitutively active as determined by an in vitro kinase assay, being independent of PKC activators, e.g. phosphatidylserine and phorbol ester. PKCthetaII may play a crucial role in spermatogenesis or some related function of the testis.

HPLC profile analysis of hepatoprotective oleanene-glucuronides in Puerariae Flos.

In order to confirm the constitution of hepatoprotective oleanene glucuronide (OG), HPLC profile analyses of the total OG fractions of both Puerariae Thomsonii Flos (the flowers of Pueraria thomsonii) and Puerariae Lobatae Flos (the flowers of P. lobata) were performed. No remarkable difference in the HPLC profiles with respect to OGs in the flowers was shown, in contrast to those of the roots. By repeated chromatography of the total OG fraction of Puerariae Thomsonii Flos, soyasaponin I (1), kaikasaponin III (2) and kakkasaponin I (3), which had been already isolated from Puerariae Lobatae Flos, were obtained. The hepatoprotective activity of 2 towards immunologically induced liver injury was significantly more effective than that of 1. This information supported previously obtained structure-hepatoprotective relationship data which was measured on another model. The structure-activity relationship information which suggested that the hydroxymethyl group of the galactosyl unit would enhance the hepatoprotective activity was also substantiated.

Pharmacological studies on Puerariae flos III: protective effects of kakkalide on ethanol-induced lethality and acute hepatic injury in mice.

Kakkalide, one of the major isoflavonoid components of Puerariae flos, has been investigated for its effect on ethanol-induced intoxication and on hepatic injury, including hyperglycaemia, in mice. Kakkalide reduced mortality associated with administration of ethanol. At doses of 100 and 200 mg kg-1 the effect of kakkalide was significant. The same dose of kakkalide prevented increased serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase activity. At a dose of 200 mg kg-1 it also counteracted ethanol-induced elevation of glucose levels. These results suggest that kakkalide might be useful for counteracting the effects of alcohol and might be effective for treating hepatic injury.

Effect of gonadotropin releasing hormone on thermoregulatory vasomotor activity in ovariectomized female rats.

To investigate the effect of gonadotropin releasing hormone (GnRH) on thermoregulatory skin vasomotion, we injected GnRH into various brain regions in both anesthetized and unanesthetized ovariectomized female rats. Local warming of preoptic area (PO) elicited skin vasodilation in anesthetized rats. Injection of 2 microg GnRH into the septal area lowered the threshold hypothalamic temperature for skin vasodilation at least for 2 h. Similar injections of 2 microg GnRH into the lateral ventricle (LV) and PO were ineffective. Although this vasodilative effect was also obtained after the injection of 20 ng GnRH into the septal area, injections of 2 ng GnRH were without effect. Not only injections of 20 ng Antide, a potent GnRH antagonist, but also injections of the mixed solution of 20 ng GnRH and 20 ng Antide were also without effect. In unanesthetized and unrestrained rats at an ambient temperature of 17 degrees C, injections of 20 ng GnRH into the septal area elicited tail vasodilation lasting for 30 minutes, whereas vehicle injections were ineffective. Injections of 20 ng GnRH into LV and PO were also ineffective. These results indicate that GnRH can elicit thermoregulatory skin vasomotion by acting on GnRH receptors in the septal area. This thermoregulatory vasodilative effect of GnRH might be possibly related to the etiology of climacteric hot flush.

Hypothalamic network for thermoregulatory shivering.

Warming one side of a rat's preoptic area and anterior hypothalamus (POAH) suppresses shivering on both sides of the body, and the present study evaluated the extent to which signals mediating this suppression cross the midline within and below the POAH. Hind paw shivering during unilateral POAH thermal stimulation was measured for rats in which the POAH had been midsagittally transected and for rats in which one side of the hypothalamus had been coronally transected just caudal to the POAH. In midsagittally transected rats, unilateral warming on either side of the POAH suppressed shivering equally on both sides of the body. In unilaterally transected rats, POAH warming on the transected side did not affect shivering, but warming the intact side suppressed shivering equally on both sides of the body. When a unilateral transection of only the lateral part of the hypothalamus included the medial forebrain bundle, the effect was the same as that of a unilateral transection of the whole hypothalamus. These results indicate that no information controlling shivering is exchanged between the left and right POAH and that efferent signals from the POAH, descending through the medial forebrain bundle, cross the midline somewhere below the hypothalamus to innervate both sides of the body equally.

Hypothalamic network for thermoregulatory vasomotor control.

Warming one side of a rat's preoptic area and anterior hypothalamus (POAH) causes skin vasodilation on both sides of the body, and the present study evaluated the extent to which signals mediating this vasodilation cross the midline within and below the POAH. Hind paw vasomotion during unilateral POAH thermal or electrical stimulation was measured for rats in which the POAH had been midsagittally transected and for rats in which one side of the hypothalamus had been coronally transected just below the POAH. In midsagittally transected rats, unilateral POAH thermal or electrical stimulation produced bilateral paw vasodilation, but the ipsilateral dilation occurred at a hypothalamic temperature lower than that at which contralateral dilation occurred. In the unilaterally transected rats, unilateral POAH warming produced bilateral vasodilation and, regardless of which side of the POAH was warmed, the threshold stimulus temperature was always lower for vasodilation on the intact side. Unilateral transection of a part of the hypothalamus that included the medial forebrain bundle had the same effect as did unilateral transection of the whole hypothalamus. Information controlling thermoregulatory vasomotion thus crosses the midline both within and below the POAH. Although efferent signals descending through the medial forebrain bundle innervate skin blood vessels on both sides of the body, this innervation is stronger on the ipsilateral side.

Responses of thalamic and hypothalamic neurons to scrotal warming in rats: non-specific responses?

Activities of thalamic and hypothalamic neurons in response to scrotal temperature change were investigated in urethanized (1.2-1.5 g/kg) rats with special attention to changes in cortical electroencephalogram (EEG). Somatosensory relay neurons were identified electrophysiologically in the ventrobasal complex (VB) of the thalamus. These neurons had tactile receptive fields in areas outside the scrotum. Forty out of 44 of these neurons responded to scrotal warming by increase in firing rate. The responses occurred abruptly at threshold temperatures ranging from 31 to 40 degrees C (switching response) with simultaneous changes in EEG from high to low voltages (desynchronization). In both the thalamus and the hypothalamus, neurons excited or inhibited by scrotal warming were also excited or inhibited, respectively, by noxious stimulation that produced EEG desynchronization. Neurons showing no response to scrotal warming were not affected by noxious stimulation. In deeply anesthetized (2.5 g/kg urethane) rats, VB relay neurons responded to tactile stimulation of their receptive fields, but scrotal warming produced no change in either EEG or activities of thalamic and hypothalamic neurons. These facts suggest that the responses of thalamic and hypothalamic neurons to scrotal warming may be 'non-specific'. Most thalamic and hypothalamic neurons showing switching responses did not appear to mediate specific information concerning scrotal skin temperature.