Disease relevance of Penile Erection

• The 13 subjects (group A), aged 55 +/- 8 years, had acceptable metabolic control (HbA1c, < 8%); no arterial or venous diseases or initial Peyronie's disease, as evaluated by penile Doppler ultrasonography and intracavernous prostaglandin E1 injection; and penile tumescence at the base (PTB) < 30 mm [1].
• Nitric oxide and penile erection: is erectile dysfunction another manifestation of vascular disease [2]?
• Treatment with the antidepressant trazodone has been associated with the occurrence of prolonged penile erection and priapism [3].
• However, pretreatment with 5, 10 and 20 mg/kg i.p. trazodone enhanced dexamphetamine stereotypy, and antagonized haloperidol catalepsy, ergometrine-induced WDS behavior and fluoxetine-induced penile erections [4].
• Other apomorphine-induced effects in mice and rats such as climbing, hypothermia, hypo- and hyper-locomotion, penile erections and stereotypies were not significantly modified by SR 48692 [5].

Psychiatry related information on Penile Erection

• Somewhat stronger is evidence that erection in some contexts (e.g., nocturnal penile tumescence (NPT) in humans or touch-stimulated erection in rats) is more sensitive to androgen levels than in other contexts (e.g., visual erotic stimuli in men or copulation in rats) [6].
• Nefazodone, with less alpha-adrenergic blocking activity, did not abnormally penile tumescence beyond REM sleep [7].
• Hormone treatment facilitates penile erection in castrated rats after sleep deprivation and cocaine [8].
• I.p. IMI pretreatment inhibited the penile erections (PE) and stretching and yawning (SY) typically elicited by N-n-propylnorapomorphine (NPA), a well-known CNS dopamine (DA) receptor stimulant, injected either i.p. or i.c.v., whereas it enhanced stereotyped behavior (SB) [9].
• RESULTS: Testosterone and carnitines significantly improved the peak systolic velocity, end-diastolic velocity, resistive index, nocturnal penile tumescence, International Index of Erectile Function score, Depression Melancholia Scale score, and fatigue scale score [10].

High impact information on Penile Erection

• Using behavioral tests, we found that Tat-3L4F or Ro600175 blocks conditioned place preference of THC or nicotine, and that Ro600175, but not Tat-3L4F, produces anxiogenic effects, penile erection, hypophagia and motor functional suppression [11].
• Antagonism of Rho-kinase stimulates rat penile erection via a nitric oxide-independent pathway [12].
• Nitric oxide, released from non-adrenergic/non-cholinergic nerves, is considered the principle stimulator of cavernosal smooth muscle relaxation, however, the inhibition of vasoconstrictors (that is, norepinephrine and endothelin-1, refs. 5-9) cannot be ignored as a potential regulator of penile erection [12].
• Nitric oxide: a physiologic mediator of penile erection [13].
• These findings not only support the contention that VIP may be the principal neurotransmitter involved in penile erection, but also suggest that depletion of this powerful vasodilatory peptide may play a key role in the development of penile impotence [14].

Chemical compound and disease context of Penile Erection

• Penile duplex ultrasonography with papaverine injection appears to be a useful objective method to evaluate vasculogenic impotence and to correlate favorably with nocturnal penile tumescence monitoring [15].
• (-) Eticlopride (0.025 and 0.05 mg/kg), a DA D2 antagonist, counteracted cocaine-induced motor hyperactivity but not penile erection, which it enhanced [16].
• Treatment of persistent penile erection and priapism using terbutaline [17].
• This study was undertaken to find out whether sleep-related penile erections occur in the carbachol-induced rapid eye movement sleep model in rats [18].
• Recently, nitric oxide was shown to be a mediator of penile erection in men and the nitric oxide donor linsidomine chlorhydrate (SIN-1) was introduced as a novel treatment option in patients with erectile dysfunction [19].

Biological context of Penile Erection

• All subjects had nocturnal penile tumescence once per week or less, andropause symptoms, and a serum T level of 15 nmol/liter or less and/or a serum SHBG level greater than 30 nmol/liter [20].
• Self-reports of sexual behavior, recordings of nocturnal penile tumescence (NPT), and sex steroid levels were obtained during each treatment period [21].
• Nitric oxide (NO) may mediate penile erection by inhibiting smooth muscle of the corpora cavernosa, thereby allowing vasodilation of the corpora [22].
• These findings suggest clonidine could act locally in the penile structure to suppress penile erection, possibly resulting from a penile vasoconstriction involving alpha 2 adrenoceptor [23].
• These data suggest that the facilitatory action of androgens on penile erection involves the up-regulation of both constitutive NOS isoenzymes in the corpora cavernosa [24].

Anatomical context of Penile Erection

• It is felt that an alteration in dopamine autoreceptor function may be occurring in the central nervous system of rats at approximately seven months of age rendering them incapable of responding to apomorphine with penile erections [25].
• PURPOSE: To investigate whether the paraventricular nucleus of hypothalamus (PVN) is involved in the central regulation of apomorphine-induced penile erection in the rat, and to decipher dopamine receptor subtypes in the PVN that are involved in apomorphine-induced penile erection [26].
• We previously reported that cocaine may induce activation of cortical (cEEG) and hippocampal (hEEG) electroencephalographic signals, concurrent with inhibition of penile erection, via an action on the hippocampal formation [27].
• Despite its inability to reduce penile erection and NO2- increase induced by SR 141716A when injected into the PVN, d(CH2)5Tyr(Me)-Orn8 -vasotocin (1 microg) reduced almost completely penile erection without reducing paraventricular NO2- increase when injected into the lateral ventricles 15 min before SR 141716A [28].
• The role of cyclic adenosine monophosphate, cyclic guanosine monophosphate, endothelium and nonadrenergic, noncholinergic neurotransmission in canine penile erection [29].

Associations of Penile Erection with chemical compounds

• Cimetidine, but not ranitidine, inhibits penile erections in rats [30].
• Transdermal nitrate, penile erection, and spousal headache [31].
• Activation of dopamine D4 receptors by ABT-724 induces penile erection in rats [32].
• Penile erection elicited by papaverine is reduced profoundly in mice with targeted deletion of eNOS [33].
• The generation of nitric oxide (NO) in penile erectile tissue and the subsequent elevation of cyclic GMP (cGMP) levels are important for normal penile erection [34].

Gene context of Penile Erection

• CONCLUSIONS: eNOS mediates NO-dependent penile erection in nNOS- animals and normal penile erection [35].
• The contribution of the neuronal and endothelial isoforms of nitric oxide synthase (nNOS and eNOS, respectively) in the synthesis of nitric oxide as a mediator of penile erection, at the levels of both the penile corpora cavernosa and the hypothalamic regions that control the erectile response, are well established [36].
• The pleiotropic effects of inducible nitric oxide synthase (iNOS) on the physiology and pathology of penile erection [36].
• Our results suggest that eNOS contributes significantly to the physiology of penile erection [37].
• The data provide a molecular explanation for VEGF stimulatory effect on penile erection, which involves phosphorylated eNOS (Serine 1177) mediation [38].

Analytical, diagnostic and therapeutic context of Penile Erection

• Activation of these neurons by dopamine and its agonists, excitatory amino acids (N-methyl-D-aspartic acid) or oxytocin itself, or by electrical stimulation leads to penile erection, while their inhibition by gamma-amino-butyric acid (GABA) and its agonists or by opioid peptides and opiate-like drugs inhibits this sexual response [39].
• The current study was performed to determine whether these testosterone effects are mediated via its conversion to dihydrotestosterone (DHT), and to what extent the synthesis of the mediator of penile erection, nitric oxide, is affected by castration and androgen replacement [40].
• We therefore designed an in vivo animal model to elucidate the influence of VIP and VIP antibody on the different stages of penile erection [41].
• CONCLUSIONS: The effect of vardenafil on penile erection after oral administration was clearly demonstrated in the conscious rabbit model [42].
• Testosterone replacement (50 micrograms/kg/day for 23 days) partially reversed the effect of hypophysectomy on penile erection, but not on yawning [43].

References