Biomedical subjects

G Italiano

Publications and source records attributed to G Italiano.

12 recordsLinked to original sources

PubMed1996

Physiological aging and penile erectile function: a study in the rat.

Erectile function of adult (8-month-old) and aged (27-month-old) rats was investigated by in vivo and in vitro assays. Reflexogenic tonic erections were evoked in vivo by electrostimulation of the dorsal nerve of the penis. Aged rats developed tendentially low intracavernosal pressures, and the kinetics of erection and detumescence were significantly lower than in adult animals. The erectile tissue isolated from aged rats exhibited poor response to papaverine. When precontracted with norepinephrine, aged tissues required a 3-fold increase of papaverine concentration to full relaxation. Functional measurements were coupled with morphological analysis of elastic fibres of the tunica albuginea. Light microscopy showed degenerative signs of elastic fibres of aged rat specimens. Taken together, the present findings show that physiological aging is associated with penile tissue stiffness and abnormal corporal compliance.

Aging↗

PubMed1995

Effects of prostaglandin E1, and papaverine on non-neurogenic and neurogenic contraction of the isolated rabbit erectile tissue.

Experiments were performed to get further insights into the erectogenic mechanism of prostaglandin E1 (PGE1), which was compared to that of papaverine (PAP). PGE1 and PAP were effective in abolishing the contraction induced by N-ethylmaleimide (NEM), an adenylate cyclase blocker. However, preincubation with PGE1 but not with PAP markedly attenuated the amplitude of adrenergic nerve mediated contraction following prolonged electrical field stimulation. Preincubation with PGE1 was ineffective in counteracting the increase in tension due to exogenous norepinephrine. These data together with previous studies corroborate the hypothesis that in the presence of PGE1 a dual erectogenic mechanism takes place in modulating the cyclic-adenosine-monophosphate metabolism of the cavernous smooth muscle cell as well as the release of norepinephrine from the sympathetic terminal.

Alprostadil↗

PubMed1995

Bladder function in the aged rat: a functional and morphological study.

This study was designed to characterize urinary bladder function in the aged rat (27 months of age). For comparative purposes, two different control groups were included into the experimental protocol: normal 6-month old and hyperdiuretic 6-month old rats. Increased threshold volume for micturition and increased bladder mass were found in both aged and hyperdiuretic rats. No difference in the amplitude of micturition contractions was detected between groups. In the aged rat, but not in the hyperdiuretic one, augmented threshold volume and bladder mass were associated with increased intravesical pressure at micturition and structural changes of intramural bladder innervation. When activated, the vesicovesical reflex did not show any change in terms of rate of isovolumetric contractions. In the aged rat, altered sensory information on the state of maximum fullness seems to play an important role in determining abnormal cystometric findings.

Age Factors↗

PubMed1994

A simplified in vitro preparation of the corpus cavernosum as a tool for investigating erectile pharmacology in the rat.

This work describes a simple technique for the assessment of corpus cavernosum function in a species, the rat, representing a convenient model for basic research. We obtained measurable and reproducible responses to different pharmacological agents as well as to electrical field stimulation. In view of the present results we conclude that isolation of the erectile tissue together with the septum may constitute a valuable experimental tool for investigating both local erectile mechanisms and the action of drugs, in the rat corpus cavernosum. Data obtained in the presence of N-nitro-L-arginine and methylene blue further reinforce the concept that nitric oxide may be involved in the process of erection in the rats as well as in other animal species.

Animals↗

PubMed1993

Electrical stimulation of the dorsal nerve of the penis evokes reflex tonic erections of the penile body and reflex ejaculatory responses in the spinal rat.

An animal model using the spinal rat was characterized. Electrical stimulation of the dorsal nerve of the penis elicited reflex tonic erections of the penile body and reflex bulbospongiosus muscle activity, flips and ejaculations. The tonic erections of the penile body are independent from contractions of the bulbospongiosus muscle and appear to be the result of a neurovascular process. Our observations suggest that reflex bulbospongiosus muscle activity, flips and ejaculations are a single complex reflex response, which we define as reflex ejaculatory response. Two parameters predicted the occurrence and type of reflex response. The visualization of bulbospongiosus muscle activity during surgical isolation of the dorsal nerve of the penis was sufficient to anticipate the elicitability of reflex ejaculatory responses. The latter, together with a systemic systolic pressure > or = 73 mmHg., warranted the elicitability of reflex tonic erections. The similarities found in the physiology of rat tonic penile body erections and of human erections make this model promising for further elucidation of sexual function. Moreover, the present model may prove useful for the investigation of neurogenic erectile dysfunction, and of neurogenic ejaculatory disorders.

Animals↗

PubMed1993

Ultrastructural analysis of the cavernous and dorsal penile nerves in experimental diabetes.

The present study was designed to investigate whether experimental diabetes determines structural changes in peripheral nerves involved in reflexogenic erection, namely the cavernous and the dorsal nerve of the penis. Myelinated axons were examined in the dorsal nerve of the penis from rats with streptozotocin-induced diabetes (3- and 6-month duration). Morphometric analysis disclosed a significant decrease of myelinated fibre size most likely due to a progressive axonal atrophy. In addition, morphological analysis revealed diffuse accumulation of glycogen within axons, lipid droplets in Schwann cells and pronounced sequestration of axoplasm by adaxonal Schwann cell processes. These signs were particularly prominent in 6-month-diabetic rats. Myelinated and unmyelinated axons of the cavernous nerve were analysed in 6-month-diabetic animals. No substantial ultrastructural abnormalities were found in the cavernous nerves. These results suggest that in experimental diabetes regionally specific structural changes occur in neuronal pathways subserving erectile function.

Animals↗

PubMed1993

Effect of streptozotocin-induced diabetes on electrically evoked erection in the rat.

This study was designed to investigate whether experimental diabetes in rats could functionally affect reflexogenic erection. Erection was elicited by means of electrical stimulation of the dorsal nerves of the penis and recorded as intracorporeal pressure. Rats were examined 1, 3 and 6 months after diabetes induction by streptozotocin. Three and 6 month diabetes caused a significant decrease of latency for erection and a slower phase of detumescence when compared to age-matched controls. In addition, a trend for a lower developed intracorporeal pressure was present in the 6 month diabetes group. Our results indicate that experimental diabetes is associated with alterations of reflexogenic erection.

Animals↗

PubMed1992

Functional responses of hindlimb circulation in aged normal and WHHL rabbits.

Normal New Zealand and Watanabe heritable hyperlipidemic (WHHL) rabbits, about 24 months old, were prepared, under anaesthesia, for recording blood pressure and hindlimb blood flow. Changes in hindlimb vascular resistance were measured after local intra-arterial bolus injection of increasing doses of acetylcholine, bradykinin, serotonin, sodium nitroprusside and phenylephrine. In WHHL rabbits basal hindlimb blood flow was reduced (from 22.6 +/- 3.0 to 12.5 +/- 1.8 ml/min; P less than 0.05) and hindlimb vascular resistance was increased (from 4.6 +/- 0.5 to 8.2 +/- 1.5 mmHg/ml per min; P less than 0.05). No difference was observed in response to acetylcholine, serotonin, sodium nitroprusside and phenylephrine. The only marked alteration found in WHHL rabbits was a clear deficit to bradykinin stimulation. Morphological analysis, using scanning and transmission electron microscopy, indicated a clear damage of the femoral artery, like the presence of atherosclerotic plaques, and an abnormal distribution of patent microvessels in the WHHL muscles of the leg. Peripheral circulation in WHHL rabbits shows some peculiar features, like increased basal vascular resistance and a selective impairment of bradykinin responses. Together with these abnormalities, it seems that responses to various other dilating or contracting agents are normal, suggesting that in this interesting animal model of atherosclerosis the alterations are more specific than in other models.

Acetylcholine↗

PubMed1991

Inner ester derivatives of gangliosides protect autonomic nerves of alloxan-diabetic rats against Na+, K(+)-ATPase activity defects.

Bovine brain gangliosides have been shown to prevent decay in Na+,K(+)-ATPase activity in sciatic and optic nerves of alloxan- and streptozotocin-diabetic rats. In the search for a drug with greater bioavailability and increased incorporation into neural tissue, ganglioside inner ester derivatives (AGF1) were recently developed. We evaluated the effect of AGF1 treatment on Na+,K(+)-ATPase activity in homogenates of vagus nerve from alloxan-diabetic rats (100 mg/kg s.c.). Animals were treated with AGF1: 10 mg/kg 6 days/week i.p., or 30 mg/kg biweekly i.p. Treatment began 10 d post-alloxan and continued for 8 consecutive weeks. Normal age- and sex-matched rats were used as controls. Alloxan intoxication produced a 39% decrease in Na+,K(+)-ATPase activity of the vagus nerve, which was completely restored (96-97% recovery) by both AGF1 regimes. Results suggest that ganglioside inner ester derivatives may be used in the clinical setting for the management of diabetic autonomic neuropathy.

Animals↗

PubMed1990

Cystometric changes in alloxan diabetic rats: evidence for functional and structural correlates of diabetic autonomic neuropathy.

Autonomic neuropathy and urinary bladder function were compared in Sprague-Dawley rats with alloxan-diabetes of 3 months duration, rats fed sucrose for 8 weeks, and rats examined 8 weeks after pelvic nerve surgical axotomy; normal age-matched rats were used as controls. All experimental interventions induced bladder hypertrophy with increased bladder weight. In diabetic and sucrose-fed animals, water intake and urinary output increased. Cystometric recordings of normal rats in vivo showed rhythmic contractions (1.25 +/- 0.25 contr/min) with threshold volume for micturition reflex at 0.51 +/- 0.04 ml. In diabetic rats, bladder contractions were irregular and of lower frequency (0.60 +/- 0.04 contr/min), while threshold volume was significantly higher (1.00 +/- 0.11 ml). Bladder contractions were normal in sucrose-fed animals, though threshold volume was markedly augmented (1.27 +/- 0.19 ml). Pelvic nerve surgical ablation abolished micturition reflex. In bladder strips excised post-mortem, contractile response to field stimulation was reduced in diabetic rats compared to control and sucrose-fed animals. Morphological examination of pelvic and hypogastric nerves revealed abnormalities characteristic of diabetic neuropathy only in diabetic rats. These data suggest that in alloxan-induced diabetes the decrease in the rate of bladder contraction is the result of autonomic neuropathy; while bladder hypertrophy in sucrose-fed rats appears to be an organ adaptation to hyperdiuresis.

Alloxan↗

PubMedDate not supplied

Urine retention due to intra-spinal cord injection of colchicine in rats: improved recovery of bladder function by monosialoganglioside GM1 and nerve growth factor administration.

Intra-spinal cord injection of a low dose of colchicine (2 micrograms/rat) at the lumbar level affects the micturition reflex leading to voiding suppression, bladder hypertrophy and overflow incontinence which lasts about four weeks. The administration of nerve growth factor and monosialoganglioside GM1 normalizes urine output within 3 days and improves recovery of the bladder contraction tested by a cystometric analysis.

Animals↗

PubMedDate not supplied

Diabetic autonomic neuropathy and bladder function: pharmacological use of gangliosides and insulin.

This paper briefly describes experimental evidence indicating that bladder dysfunction observed in diabetic rats is due in part to hyperdiuresis and in part to autonomic nerves alterations. The latter, in analogy with somatic nerves alteration, can be ameliorated by treatment of diabetic animals with gangliosides. The use of this agent in the autonomic nerve dysfunction of diabetic origin is discussed.

Animals↗