On the role of the dorsal mesencephalic tegmentum in the control of masculine sexual behavior in the rat: effects of electrolytic lesions, ibotenic acid and DSP 4.
The work presented here concerns the way in which the dorsal midbrain tegmentum (DMT) participates in the control of sexual behavior. It was first established that electrolytic DMT lesions accelerate mating in the male rat, primarily by abbreviating the post-ejaculatory interval. Since the effective lesions were accompanied by decreases in the in vitro synaptosomal uptake of [3H]noradrenaline (NA) in hippocampus and hypothalamus, the behavioral effects of DSP4 (which elicits degeneration in NA nerve terminals derived primarily from the locus coeruleus) were examined. The long-term behavioral consequences of DSP4, however, were to decrease copulatory rate despite substantial NA denervation of brain and spinal cord. Ibotenic acid-induced neuronal degeneration in the DMT, on the other hand, accelerated copulatory behavior while leaving NA innervation of hippocampus and hypothalamus unaffected. The magnitude of the behavioral effect in ibotenic acid-treated rats was less than that induced by electrolytic DMT lesions. It is tentatively suggested on the basis of these-experiments that DMT cell bodies may form part of a system regulating sexual arousal mechanisms, whilst activity in a non-adrenergic fiber system running in the dorsal tegmental bundle may be required for active inhibition of sexual behavior after ejaculation. In additional experiments it was found that DSP4 treatment of female rats produced negligible effects on sexual behavior, estrous cyclicity and processes related to lactation.
D000588:Amines / Q000494:pharmacology*; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000601:surgery; D004564:Electrocoagulation; D007051:Ibotenic Acid / Q000494:pharmacology*; D008297:Male; D009498:Neurotoxins / Q000494:pharmacology*; D010080:Oxazoles / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012726:Sexual Behavior, Animal / Q000187:drug effects; D013681:Tegmentum Mesencephali / Q000187:drug effects / Q000502:physiology*
D000588:Amines; D001596:Benzylamines; D009498:Neurotoxins; D010080:Oxazoles; D007051:Ibotenic Acid; C012102:DSP 4