Changes in the Vipergic, Cholinergic and Adrenergic Innervation of Human Penile Tissue in Diabetic and Non-Diabetic Impotent Males

Abstract

Penile tissue (consisting of corpus cavernosum and tunica albuginea) was obtained from 19 patients undergoing surgery for the implantation of penile prostheses. The tissue was examined for vasoactive intestinal polypeptide-like immunoreactivity in nerves, acetylcholinesterase-positive staining in nerves and noradrenaline content. Impotence was due to a variety of causes; 11 patients were classified as a 'non-neuropathic' group on the basis of their clinical history which included Peyronie's disease, vascular disease, hypertension and psychogenic impotence. Vasoactive intestinal polypeptide-like immunoreactive and acetylcholinesterase-positive nerves were present and the pattern and distribution were similar in each patient in this group. The noradrenaline content of the tunica albuginea was significantly lower than the corpus cavernosum (p less than 0.02), although there was a linear relationship between the noradrenaline contents of the two regions (r = 0.95, p less than 0.01). By comparison, a complete absence of vasoactive intestinal polypeptide-like immunoreactivity in nerves was observed in a patient with a cauda equina lesion. Five out of six diabetic patients studied revealed a marked reduction in vasoactive intestinal polypeptide-like immunoreactivity in nerves associated with the cavernous smooth muscle, while acetylcholinesterase-positive staining was reduced in three out of five diabetic patients studied. The noradrenaline content of the corpus cavernosum from diabetic patients was significantly lower (p less than 0.02) than that of the 'non-neuropathic' group. The noradrenaline content of the tunica albuginea, however, was similar in both groups. The results provide evidence that VIPergic, cholinergic and adrenergic nerves in the penis are affected in diabetes mellitus and thus may contribute to the development of impotence in diabetic patients.

Diabetic Cystopathy: Neuropathological Examination of Urinary Bladder Biopsies

“…Similar findings in the corpora cavernosa of impotent diabetic patients were described [11], Recently, reduced AChE staining in penile tissue was found in a number of impotent diabetic patients as compared to non-diabetic impotent males [12] tylthiocholinesterase staining was done following a modified Karnowsky method on cryostat sections. After paraformaldehyde fixa tion the slides were incubated in a solution with acetylthiocholine iodide, CuS04 and potassium ferricyanide.…”

Effects of diabetes on neurotransmission in rat vaginal smooth muscle

“…29,31 Melman et al and Lincoln et al found a reduction of the NA content in nerve ®bers in corpus cavernosum from diabetic men compared to non-diabetics. 32,33 These studies illustrate that with regard to a-ARmediated responses, diabetes-induced changes in smooth muscle may be organ andaor species dependent.…”

“…5,34 In the vascular bed, several investigators have shown that diabetes causes impaired endothelium-dependent relaxation. 35 ± 38 Possible mechanisms behind the diabetes-related impairment of the NO system may be decreased releaseaformation of NO due to decreased NOS activity, 39 de®cit in the substrate availability, 35 alterations of the NOS binding sites, 34 reduction in nerve density, 33 or decreased sensitivity to NO. 36 In order to identify a possible step of the cGMP pathway responsible for the diabetes related impairment of the NO system in our experiments, investigations were carried out to measure NOS activity in tissue from diabetic and non-diabetic animals.…”

Mechanisms of Penile Erection and Basis for Pharmacological Treatment of Erectile Dysfunction

“…It seems that most of these NOS-and VIP-containing neurons are cholinergic, because they also contain vesicular ACh transporter (Hedlund et al, 1999), which is a specific marker for cholinergic neurons (Arvidsson et al, 1997). In patients with diabetes and ED, some investigators found a marked reduction of VIP-like immunoreactivity in nerves associated with the CC smooth muscle (Gu et al, 1984;Lincoln et al, 1987), but others did not (Haberman et al, 1991). In addition, the results of animal studies on the role of VIP in penises of diabetic animals are conflicting (Miller et al, 1995;Maher et al, 1996).…”