Sexual dysfunction in women with diabetes mellitus: Addressing impaired arousal

Sexual dysfunction in women with diabetes mellitus

Sexual problems in men with diabetes mellitus are common and often result from diabetic complications. However, although diabetic complications are similar in both sexes, little attention has been given to the effects of diabetes on female sexuality and sexual function. It is reasonable to suggest that women with diabetes will experience sexual problems due to neuropathy, endocrine changes and vascular complications. However there is little research into the physical effects of diabetes on female sexual function. Reduced vaginal lubrication in women with diabetes has been reported yet this is rarely documented as a sexual problem. Previous studies in women with diabetes may also neglect the importance of the subjective qualities associated with female sexuality and sexual expression.

Effects of diabetes on neurotransmission in rat vaginal smooth muscle

The aim of this work was to characterize the effect of experimental diabetes on neurotransmission in rat vagina. Female Sprague-Dawley rats were divided into two groups: non-diabetic controls (NDM, n=38) and diabetics (DM, n=38). DM was produced by intraperitoneal injection of streptozotocin. Eight weeks later the animals were killed, the distal part of the vagina was removed, and smooth muscle strips were prepared for functional organ bath experiments and for measurement of nitric oxide synthase (NOS) activity. In DM preparations, the EC(50) value for noradrenaline (NA) was significantly increased (P<0.05) and the maximal contractile response decreased (P=0.001). In preparations precontracted with NA, the NO donor SNAP and calcitonin gene-related peptide (CGRP) caused concentration-dependent relaxations, which were significantly decreased (P<0.001) in the DM group. Electrical stimulation of nerves (EFS) caused frequency-dependent contractions, which were significantly lower in DM than in NDM strips (P<0.001). SNAP and CGRP concentration-dependently inhibited EFS evoked contractions in both NDM and DM preparations. The inhibition was significantly lower (P<0.05) in the DM group. In NDM preparations precontracted with NA, EFS evoked frequency-dependent relaxations; such relaxations were inhibited or reduced in DM. Treatment with the NOS inhibitor, L-NOARG 0.1 mM, abolished relaxations in all preparations or produced contraction in DM preparations. Calcium-dependent NOS activity was not significantly different in the DM and NDM groups. However, the DM animals showed a small but significant increase in calcium-independent NOS-activity (P<0.05). Diabetes interferes with adrenergic-, cholinergic- and NANC-neurotransmitter mechanisms in the smooth muscle of the rat vagina. The changes in the nitrergic neurotransmission are not due to reduction in NOS-activity, but seem to be due to interference with later steps in the L-arginine/NO/guanylate cyclase/cGMP system.